"I'm thinking I'll kill my homeroom teacher! To run into someone and not apologize? So rude!"
- ―Akane Shinjo
Subtitle: Retribution Monster (因果応報怪獣 Ingaōhō Kaijū)
Akane decided to unleash Dévadadan with Alexis's help after her homeroom teacher bumped into her at school and did not apologize. Using the Instance Abreaction on Dévadadan's figure, it was turned into a real monster that proceeded to hunt down the teacher and attempt to destroy him. Gridman appeared to combat the threat but its laser counter ability nullified the Grid Beam. After Samurai・Calibur became the Gridman Calibur, the monster was destroyed by the Grid Calibur End finisher. With the teacher surviving the ordeal to the next day, Dévadadan failed its mission. Ironically, the incident had taught said teacher to reduce his smartphone addiction, evidenced by his apology to Yuta by the next day.
Dévadadan, along with all the other kaiju Gridman fought, reappeared when they were summoned by Alexis to get rid of Gridknight, since Akane refused to make any more new kaiju. Dévadadan, along with Ghoulghilas was finished off by the Gridknight Storm.
- Designer: Shinji Nishikawa
- Its crystallized body design is an allusion to Gilarus. Meanwhile, the presence of colorful circuit lines is based on Ultraman Exceed X.
- It also resembles Dada with its white and black body and large pink lips. Dada can also be found within Dévadadan's name.
- The way it cuts off the top of a building and causes debris to almost land on the Gridman Alliance is very similar to what Maga-Grand King did to the SSP in episode 2 of Ultraman Orb.
- Powers and Weapons
- Laser: From the spike on its chest, Dévadadan can fire a destructive laser.
- Laser Counterattack: Dévadadan can absorb an incoming energy attack and redirect it back to the sender.