"Gouki" have wrestling themes in their design and name, shown in the fact that they are wearing tights as well as their golden championship belt. Each one is based off of an animal, or creature in "Gouki the Great Ogre's" design, drawing heavy elements from it. Their championship belt also has the face of their themed animal/creature, and their helmets fit the theme of their animal as well. They also are suited up in padded armor and wielding weapons. They also have a predominantly single colored theme. So far the Main Deck monsters have a primary/secondary color while their only Link Monster is a neutral color. The monsters resembles in term of style, the Elemental HEROs.
"Gouki" (剛鬼) can be translated as "strong ogre". The Main Deck "Gouki" monsters are named after wrestling moves, such as Suplex, and then their appearance is based off an animal whose name is in the wrestling move name, such as "Gouki Twist Cobra" being based off a cobra, or creates a pun based off that animal's name, such as "Gouki Suplex Rex" being a pun on T-Rex (SupREX).
The "Gouki" monsters seem to focus on a straightforward aggressive strategy, using effects to increase their ATKs or decrease the opponent's. The Main Deck monsters have 0 DEF, being immune to the effect of "Gouki the Great Ogre", who, in turn, has no DEF; that makes it so that they generally have an advantage over the opponent's monsters' ATKs, since those will be reduced while their own won't.
The Main Deck monsters all have the effect "If this card is sent from the field to the Graveyard: You can add 1 "Gouki" card from your Deck to your hand, except [itself]", replacing thenselves when used as Link and Synchro Materials, or used with cards like "Transmodify" and "Spiritual Earth Art - Kurogane".