Here is the inspiration of Yamada that related to the other villains.
- Yuuki Terumi (BlazBlue series) - They're both main villains, famous archenmies and manipulative masterminds.
- Darth Sidious/Emperor Palpatine (Star Wars franchise)
- Dio Brando (Jojo's Bizare Adventure)
- Frieza (Dragon Ball franchise)
- Joker (DC Universe)
- Green Goblin (Marvel Universe)
- Plankton (SpongeBob Squarepants)
- Dr. Eggman (Sonic the Hedgehog series)
- Zim (Invader ZIM)
- Aku (Samurai Jack)
- Dong Zhuo and Sima Yi (Romance of the Three Kingdoms/Dynasty Warriors)
- Judge Claude Frollo (Disney's The Hunchback of Norte Dame)