Lets just get this done

Time skip next day

After all the classes the entire class besides izuku walked into the common room to see Rias's family and a blonde ass hat. You know who. Riser phenex
"My beloved Rias how are you?" The scumbag asked "For the last time I will not fucking marry you, I'm gonna marry who I want!" Rias yelled at him. Everyone in the class looked Hella confused. "Young lady I did not raise you to speak like that!" He father yelled right back. Rias mother told him off. Then they began fighting. "Woah Rias are sure you can't beat this weak ass knock off of a rip off Phoenix." Izuku said walking in with a drink in hand. "What did you call riser you peasant!" Riser yelled in rage while throwing a fire ball in which was negated. "I challenge Riser Phenex for Rias's hand in marriage." Izuku straight exclaimed making all the girls face go from confused to shock. "Why would I allow you to try?" Rias's father asked. "Because I could have you absolutely destroyed in both the human world and the supernatural." Izuku said with a smirk across his face. "And according to supernatural law. When someone is put in an arranged marriage of any kind. Anyone can challenge for a hand in marriage. And I could simply report this the Japanese government." Izuku said (Check and mate) izuku thought. "Riser accepts your challenge." Riser said. "ill give 10 days to prepare." Riser said vanishing with Rias's family. Izuku then teleported him and Rias to his room.

"Thank you izuku." Rias said "Wait a damn minute I thought you would be pissed that I was trying to take his place instead of getting you out of the marriage." Izuku exclaimed in shock "I would rather it be you then anyone." Rias confessed.

Timeskip 10 days later

"You know you can still back out." Riser said with an arrogant look. "What wrong Mc Fly chicken?" izuku asked with a smirk. As izuku and riser got teleported to a battle field. Izuku and Riser were standing across from each other. Riser and Izuku dashed at each other and began throwing punch after punch. Seeing they were equal with all Izukus seals on. Izuku nor Riser were bruised because regeneration. "Hey Riser do you have a stronger form then this?" Izuku asked "No I don't why." Riser asked. (He's not lieing good.) "That's means this battle is mine." Izuku said calmly. Then began floating

It is I who is Supreme

With a twitch
All of which exist came to be
With a thought
All of which can be destroyed
I shall destroy then create anew
All shall obey the command
Let your soul pass on
For stepping to me
Is the last mistake you make

Supreme Drive

Izuku's aura alone made all bow to him. This was his weakest release state. One were Izuku deletes his first seal from exist. The fight went from equal on both sides to a one-sided homicide. Izuku proceeded to land mikey's 360 kick into issiki's chain combo to a tailed beast beat down to a 5 piece and finally a totsuka blade to the chest. Sealing him away for eternity.

Eternal
Demon
Out