Erik Jimenez

Web Developer in Toronto, Ontario, Canada

Guyver for D20 Modern

Guyver for D20 Modern (May 18, 2006)

Guyver for D20 Modern

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Guyver for D20 Modern is a Guyver-based conversion for the D20 Modern role-playing game. Guyver for D20 Modern can also be used for the regular role-playing game, Dungeons & Dragons.


The inspiration for this work was Majikthise's document on how to use the Guyver in a RIFTS© RPG campaign. It can be found on Guyver Four's Bio Booster Armor Guyver web page at Other sources include the documents found at, which has adaptations for several other anime storylines, and where the moderator has turned the Guyver story into a template for use in 3rd Edition Dungeons and Dragons campaigns. The following information was created during my spare time, with the aforementioned sources used as references only to ensure balance. After all, if you're too powerful, what fun is the game going to be?

Much of the "finer" details will be left out so you don't have to waste your time re-reading much of what you probably already know, only game important information will be repeated. If you want to find out the complete history and anatomy of the Guyver, Majikthise's document is good reading if you want it all in one place. While reading is usually good, you could always get the manga and anime, right? The following page is divided into several sections and appears in the following order:

To go to a specific section, hit Ctrl+F and enter the location you want. For example, type W6 into the search box if you want to go directly to the section on Weaponry.

(B1) Bio-Booster Armor Guyver

The Guyver unit can only be activated by humanoids and monstrous humanoids although the Guyver armor reacts more radically with humans than other races. Regardless of the host creature, all Guyver units are similar to one another in appearance. Coloring, location and quantity of arm blades, as well as the exact placement of the eyes and head-sensors vary between units, regardless of host. Configuration of the chitinous plates varies, depending on the physical characteristics of the host. All of the Guyver's abilities apply only when the armor has been summoned.

(A2) Activating a Guyver Unit

When a suitable host activates a Guyver unit (by placing the Control Metal against the host's forehead), the shock of bonding with the unit renders the host unconscious (no actual loss of hit points is incurred) unless they succeed on a DC 30 Will save. If the host succeeds, they remain conscious after bonding. If they fail the save, the host is considered unconscious and the newly formed Guyver (the host and unit are now treated as one being) goes into Self Defense Mode for 1d4 hours. Once activated, the Guyver armor is permanently bonded to the host; there are no known means of severing the Guyver from its host.

(S3) Summoning the Bio-Booster Armor Guyver

While not in use, the armor is stored in a pocket dimension (similar to a Bag of Holding) and can be called upon using the telepathic organism in the host's back. The organism near the host's shoulders appears to be burn scars unless more closely examined. After any attempted removal, they will re-grow within 30 minutes. Summoning the Guyver armor requires a DC 15 Concentration check until level 10. By now the host should be so intimately familiar with the Guyver that its use becomes reflexive and like second nature. The Guyver host can create a command word that helps the user focus (-2 to Concentration DC check). The command word is usually shouted at the moment before the armor is activated, to help create the focus needed, making the activation obvious to those who hear it. Next is a thunderous bang and a discharge of energy from the host's chest that deals 3d8 damage to the surrounding area (Reflex for half damage). The explosion and noise is caused by the Guyver armor piercing the barrier between the pocket dimension and the host's dimension. Excluding shrapnel, all damage is contained within a 5-foot sphere, the center located at the host's chest. The Guyver surrounds the host, including clothes and any non-metallic armor equipped. Metal (like splint or plate-mail), or bulky armor (like leather, banded, or padded) is ripped from the host, flying in all possible directions as shrapnel (hard materials deal 1d3 damage, softer materials deal 1 damage, Reflex DC 15 negates all damage). Tight fitting clothes are not destroyed but instead are covered by the Guyver armor and remain after the armor is removed. The Guyver armor can be removed by simply willing it away. When the Guyver is removed, the host returns to their regular form; all bonuses are lost until the Guyver armor is summoned again. After the Guyver is removed the host must rest for 1d6 hours, due to the Guyver feeding off of the host's energy.

(G4) The Guyver

The next section details what bonuses are granted to the host when the Guyver is in use. Some bonuses stack with the host's and others will not. There are two columns, one for regular humans and one for non-humans. The non-human category will encompass both humanoids and monstrous humanoids.

  Human Non-Human
# of Attacks 2 extra attacks 1 extra attack
STR +10 +5
CON +5 +2
DEX +5 +2
CHA -5 -10
BP 2xCon +4/lvl 2xCon +2/lvl
Speed x4 x2
Jump x5 x3
Saves (All) +4 +3
Defense (AC) +5 +2
HP +2xCon +Con
  • Humans can fly at 3 times their base land speed with Good Maneuverability at a cost of 1 BP per 2 rounds. Humans also heal at a rate of 2 HP per round while the Guyver is in use. Being a type of armor, the Guyver grants its human host +5 to its Defense (AC). It also increases the host's HP by 2 times the hosts (new) Constitution score. These are not like temporary hit points, which are lost first.
  • Non-Humans can fly at 2 times their base land speed with Clumsy Maneuverability at a cost of 1 BP a round. Non-Humans regenerate at 1 HP per round while the Guyver is in use. Being a type of armor, the Guyver grants its non-human host +2 to its Defense (AC) and increases its HP by the hosts (new) Constitution score.
  • All hosts are granted immunity to mind control effects and natural diseases and poisons. A host also gains +3 to their saves against magical diseases and poisons.
  • Due to the sustaining nature of the Guyver armor, a host can live 50-75% longer than other beings of the same race. The host is also treated has having the Timeless Body ability, meaning that the host no longer appearsages past "Adult," takes no penalties from aging, and continues to gain the bonuses from aging. When the host's time is up, they still die as normal.

Guyver Construction

The exact material used to produce a Guyver is unknown, as the beings that created it have long since disappeared. Despite this fact, the Guyver is a purely organic being, meaning it can be damaged as well. The Guyver armor regenerates damage it receives almost immediately, meaning that keeping track of damage to it is not necessary. Chitinous plates cover and protect key parts of the host's body while a tendril like wrapping fills in the gaps between different parts of the armor. Because of the unique methods and materials used to "grow" the Guyver units, it affords the host complete life support, rendering gas attacks, underwater locations, and even the extreme temperatures and vacuum of deep space not a problem. The Guyver's construction also grants the host Damage Reduction 10/- and Energy Resistance 10 against fire, cold, electricity, and sonic/concussion damage except for ACID (ER 10/acid). Highly potent acids (dealing 15 or more points of damage at minimum) are the only thing that can overcome the Guyver's damage resistance and energy resistance. The damage from acids takes twice as long to regenerate.

Control Metal

The Control Metal is what regulates power for the Guyver. It is fragile while the Guyver unit is not bonded with a host. In its un-bonded state, the control metal has 30 HP, a Defense (AC) of 11, and a hardness of 15. After the Guyver unit has bonded with a host, it is near invulnerable. The only way to destroy a Guyver is to remove the Control Metal. If the Control Metal is singled out and attacked, the shock of the attack will cause the Guyver to be stunned for 1 round unless it succeeds on a DC 25 Fortitude save. To remove the Control Metal, you must succeed on an attack on the Control Metal (at a -3 penalty because of the necessary precision), grapple the Guyver, and then attempt to pull the Control Metal out of the Guyver's forehead by making a DC 30 Strength check. Doing so destroys the Guyver, causing it to dissolve in a heaping mass of ooze. The removed Control Metal is now vulnerable to attack, with 50 HP, a Defense (AC) of 15, and hardness 20. Destroying the removed Control Metal permanently destroys a Guyver. If the Control Metal is not destroyed, it will completely regenerate the Guyver (host and all) within 24 hours unless frozen or similarly encased, which will pause the regenerative process until the Control Metal is no longer sealed. The host has all its memories and abilities from the moment the Control Metal was removed as if it never died. The only thing that does not regenerate is the host's clothing and equipment. Once the Guyver is completely re-grown, it will be in Self Defense Mode until the host is healed, approximately 3 hours after regeneration is completed, unless someone is around that can help wake the Guyver host from its sleep. There is no loss of level or ability score damage from death and rebirth in this fashion.

Head Sensors

On the head of the Guyver are 2 metal hemispheres, one on each side of the head. These Head Sensors grant the user a +5 bonus on Search and Spot checks, as well as the ability to sense the location and general size of living beings. These sensors function in a 75-foot sphere around the Guyver and with the Head Sensors the Guyver cannot be flanked, caught flat-footed, and the like unless (somehow) knocked unconscious.

Sonic Generators

The Sonic Generator Orbs, located approximately where the Guyver's mouth is, have several abilities. The most obvious two uses are as a shield against solid projectile weapons and as a sonic weapon. The Sonic Generators can also reduce an object's hardness rating by 10 because of the high frequency vibrations that rattle the object to pieces. This same ability can be used to sunder an opponent's solid armor or weapon (cloth and similar items cannot be broken with this ability). If the object has a hardness rating of less than 5, it is turned to dust from the use of this ability.

Gravitonic Generator Orb

The Gravitonic Generator Orb is located about where a belt buckle might be on a regular human. This orb allows the Guyver some control over gravity, though not exactly the best. With the ability to control gravity the Guyver can fly relatively well, though most might consider the ability an advanced form of levitation. The orb also grants the Guyver a +10 bonus on Jump and Climb checks. Because the Guyver bonds more drastically with a human, they have more control over the orb, up to the point of being able to use it as a weapon. No other known creature can access this ability, part of which makes dealing with a human Guyver all the more dangerous.

(SD5) Self Defense Mode

The Guyver goes into Self Defense Mode in one of three ways: 1) After activation of the unit; 2) The Guyver/host is below 1 HP; or 3) The Guyver is subjected to mind-controlling effects. While in Self Defense Mode, the Guyver is essentially a hostile NPC that attacks any beings that appear to threaten it. There is no way for it to tell the difference between friend or foe, so the best advice is to just run while you can. The Guyver will use any weapon to get the job done, whether the host has learned how to use it or not. The Guyver remains in Self Defense Mode until the host has been healed to 3/4 HP or higher. While in Self Defense Mode, the Guyver has the following stat changes: ? HP, 35 Defense (AC), host's (new) STR, DEX, and CON +10 each, Speed 60, Initiative +8, Melee Attack bonus +12/+7/+2, Ranged Attack Bonus +8/+3. These stats are base values and can increase as the host levels up (+1/level). To determine the Guyver's HP, take the host's CON score, add any bonuses, and then add the host's level times the CON modifier to the total. Example: A level 4 human Guyver has 18 CON with a +4 modifier and has summoned the Guyver (+5 bonus to CON). The Guyver now has a CON of 23 with a +6 modifier. While in Self Defense Mode, the Guyver gets another +10 bonus to CON meaning the Guyver now has a CON of 33 and a +12 modifier. You take the CON score (33) and add 4 times the modifier (4x12) to it, giving the Defending Guyver 81 HP.

(W6) Weapons

The weapons built into a Guyver are not immediately available for use; they must be learned or unlocked. This can be done by either instruction from another Guyver who has already learned that ability, by making a DC 20 Wisdom check at the end of each combat (GM's discretion), or when the character levels up. To use a weapon after learning them, you must pay a certain amount of Bio-Points (BP). Some weapons will drain BP as they are used, but for others it is a one-time cost.

  BP Human Non-Human
Infrared Forehead Laser 2* 1d6 2d4
Sonic Emitter 4* 1d8 1d6
Pressure Cannon 8* 2d10 Not Available
Sonic Blades 6** 2d8+STR Critical 19-20x3 2d6+STR Critical 18-20x2
Mega-Smasher (Single) 1d12 per 10 BP 1d10 per 10 BP
Mega-Smasher (Both) 2d12 per 15 BP 2d10 per 20 BP

*The cost is for each use. **Once activated, there is no need for further expenditure of BP to use.

  • The Infrared Forehead Laser may only be used 3 times per summoning of the Guyver armor.
  • The Sonic Emitter is 60° cone of sound waves that extends for 5 feet from the Guyver's mouth. It lasts for 1 full round and also functions as an anti-projectile shield.
  • The Sonic Blades may extend from the wrists or the elbows. The number of blades and the direction they extend from vary between units. Roll 1d12 and consult the table below.
    1-3 4-6 7-9 10-12
    Single Blade Double Blade Single Blade Double Blade
    Wrist Wrist Elbow Elbow
  • The Mega-Smasher takes 1 full round to charge before firing. By forfeiting further actions, the host can charge up a large attack. Once fired, the Mega-Smasher will not stop until the host runs out of BP or succeeds on a DC 20 Will Save. Example: A 10th lvl Human Guyver with 76 BP charges both Mega-Smashers. He charges for 1 rds to deal 2d12 per 15BP. The Mega-Smasher will continue firing at a rate of 2d12 per 15BP until the Guyver is out of BP or it succeeds on a DC 20 Wisdom check.

Weapons can be learned in any order but the GM determines the final sequence. The following chart is a sample, complete with Wisdom Check DCs and levels they could be learned.

  Level learned Wisdom DC
Sonic Blades 1 5
Infrared Forehead Laser 2 10
Pressure Cannon 3 15
Sonic Emitters 4 20
Mega-Smasher * *
  • The use of the Mega-Smasher is restricted to GM's discretion. It is normally used near the end of combat and is too powerful to be used indiscriminately. Unless the player can think up alternate ways to control and use the Mega-Smasher, it is advised that its use remain under control of the GM.