My guy, you gotta do Rath. He’s too great and badass and silly to not be. Every other alien is intimidating in their own way, but Rath’s bluntness and showmanship would easily counter any ‘villain mastermind’. Plus I loved hearing him say: LEMME TELL YOU SOMETHING

I expected a villainous Izuku

Yeah this is nice great great

Daimondhead, Nanomech, Chromastone, Upgrade and Atomix can be the rest 5 aliens. This is my recommendation.
Great idea for fic, hope you can continue this.

MAN, THIS IS CRAZY! I really love how the story begins, it only remains to wait for the next updates.
And, I like what you did with the names, original

Looks epic! Hopefully no new fic anytime soon... Really wanna see more of this with supreme legacy.

On the sidenote... Seems local criminals are no match for Izuku though it was obvious the guys from outer space will be more of a challenge.

Either the Omnitrix reject the quirk or stood working at all. Pesky dust, toepick, Atomix, Brainstorm and Blitzwolfer.

This story is quite good. You really shine when it comes to My Hero crossovers. I would love to see this alongside Superior Legacy. Kudos for using an Adult Izuku. Breaks the monotony of thesame story being told over and over again without the need for a subplot.

As for Alien Choices...

1. Diamondhead or Chromastone - It usually one or the other and while normally I would go with Diamondhead 9/10, there could be come really cool things done with Chromastone in the MHA universe, especially as a counter ability if Master Control is unlocked. Either one is fine.

2. Wildvine - Great power set that can see a lot of use. It's shape shifting with plant control. It also doesn't overlap like Swampfire would.

3. Echo Echo - His power set is unique and versatile. He is better than Ditto and his sound attacks don't overlap with others.

4. Jetray - Jetray is actually the one alien on this list that I do not care for all that much. It is however the best choice for the team. It may fly fast and shoot lasers but it's species is actually aquatic, even faster in water than in the air. You get a flier and a swimmer all in one. Would have loved Big Chill instead but Ghostfreak...

5. Lodestar - I was thinking that anything could be in this slot. I didn't want endgame aliens like Way Big, Atomix, or God forbid Alien X. I also wanted something unique like Goop or Upgrade, and then Lodestar came to mind. Only Magne had Magnetism in MHA, and their quirk had too many conditions to it. A great power for an Urban hero.

Sweet. But Dude this should be in the crossover section. Kepp up the good work and for other I would say Gutrot, Atomix, Aerodactle and Waterhazord

Here is my choices.

Gutrot(Malchemical)
Cannonbolt(Rot8) pronounced rotate
Eyeguy(Argus) Hera 100-eyed monster
Snare-oh(Ramses)Look like a pharaoh
TimeWalker(Clockwork)

And make Katsuki Bakugou as All Mights successor. Show that bad decision making of him. Or mirio togata

Big Chill and Jury Rig have my vote.

I like what you have going on here though I admit, I thought he would have powers or skills related to a hero from the Watchmen comics but this Omnitrix thing works as well.

With the names of the alien forms, I Agee that they should be different to cannon since Izuku and Ben are too complete different people. Case in point, Izuku wanted to be a hero simply to help people while Ben was a hero because it was fun, at least at first as he changes and matures a bit in the Secret of the Omnitrix movie. Names would also be different as though Ben was creative with his alien names like Feedback and Wild-Vine, Izuku is known for being plain and somewhat uncreative so I think he'll pick names that the public gives his aleim forms.

With any new forms, I would put up Diamondhead under the name Crystal, Ripjaws known as the King Piana, Ditto under the name Mimic, Biltzwolfer known as Night Howler and Articguana under the name of... well Articguana. I kept the list to aliens Ben had when he was a kid since the Omnitrix itself seems to be the same model and hasn't evolved like Ben's did in Alien force.

I would imagine that he has people that he's told of this. Foremost bejng his mother and he didn't persure being a hero because he didn't want to worry her in the first place, he's older now and can do what he wants but I can't see him doing that to her, he would at least tell her of this since he's a terrible lair and the subject of why he has a watch would most likely came up in conversation.

Anyway, great first chapter, I hope to see more soon, take care of yourself.

Amazing first chapter I can't wait for more
And how about Big Chill as an alien?

Great and interesting story and nice touch with the hype

An AU of BNHA where Izuku never got One For All and fast forward 10 years later, All Might and All For One are dead, and we have yet to know who All Might's successor is, but on the bright side, a 25 year old Izuku Midoriya's dream of becoming a hero turns to reality when he gets the Omnitrix. Did Izuku seriously just say Azmuth created the Omnitrix for war even though he doesn't know about the Galvan scientist yet? Presumptuous much? Anyways, the first 5 aliens Izuku turns into are Heatblast, called Trailblaze, XLR8 called Strike Speed, Grey Matter called Mastermind, which I like, Ghostfreak is a name unchanged and Four Arms called Powerhouse by Izuku, which I don't mind since Izuku and Benjamin are two different characters with different traits. He's a vigilante for now, going by the name Watchman, in reference to the Omnitrix no doubt, and he's already made a huge mark, taking down villains left and right, and is dead set on filling the void left by the Symbol of Peace All Might's death.
Recommendations for the last 5 forms? I'd recommend Upgrade for Tech Manipulation, Jetray for a flyer, Gravattack for Gravity Manipulation, Atomix for massive firepower and Clockwork for Time Manipulation.