You just noticed? He has always been obsessed with iruma ever since their little fight at the school firework arc.. everytime he shows up and sees iruma he would always blush and salivate copiously. #-.-)
The last pictured is Fenrir (I think) whom Kalego's bro impersonated in the Deviculum. It's most likely Baal making a move since he seemed to be the head honcho of the villains.
With this backstory coming to light, can we just take a moment to appreciate how awesome Kalego sensei is? I really wanna see Kalego in a face off with his brother over Iruma!!! ✧
Such a green light relationship. Eujin's quirks are so adorable! (●'◡'●)ノ