So you got the cat version of yang and blake from rwby

...Aizawa is a RWBY fan and his favorite character is Blake...Yeah, that's canon now and no one can convince me otherwise!

AAAAAAAAAAA!
I'M SO HAPPY THAT AT LEAST ONE FIC IS STILL DOING HOMESTUCK REFERENCES!
I FUCKING LOVE HOMESTUCK AND I'M SO SAD THAT THE FANFICTION FANDOM FOR IT IS MOSTLY DEAD NOW!
I NEVER EVEN GOT TO ENJOY IT MUCH!

YESSSSSSSS
I'M SO HAPPY THE SYSTEM RECOGNIZED IT AS "FUCKERY DETECTION"!

LISTEN, IF IZUKU DOESN'T UNLOCK THAT SAME SPACIAL DETECTION SKILL AND IT IS /ISN'T/ NAMED "FUCKERY DETECTION", I'M GONNA BE UPSET!

FUCK, THAT WAS ALMOST LIKE EARTH BENDING AND I LOVE IT!

OH, I LIKE THIS!
THE THEORY REALLY REMINDS ME OF NARUTO'S KEKKEI GENKAIS WHERE EVERYONE HAS ACCESS TO AN INTERNAL POWER SOURCE (CHAKRA) BUT BECAUS OF GENETICS, THEY ARE MORE PREDISPOSED TO USING THAT INTERNAL POWER SOURCE IN CERTAIN WAYS
HOWEVER, LIKE IN NARUTO, IT'S POSSIBLE TO USE THAT POWER IN OTHER WAYS THAT DON'T COME AS NATURALLY TO THEM AND JUST NEED TO BE PROPERLY TRAINED!

I would think Decay as a mixture of Bio and particle because Aizawa's skin cracked like it dried out first before it was destroyed and then particle to be the force that rips it apart into dust.

Thats just my opinion so Shiggy could have two elementals that I think basing off the Flood (Halo) Bio or Leafeon Bio and Espeon Particle or Ralts Particle purely for the fact that particle could be funny while the bio could also be an eeveelution or another villanous entity even if one in Pokémon didn't quite work.

So, maybe this comes up later, but... Why isn't Izuku using the party function. I know what you said in the authors note of 5, but you were reminded about it. What was the point of even adding it if he's not going to use it?
Otherwise this is fun and I do look forward to more.

love the story

You've spun such a wonderful tale!
Keep Going! Keep Crafting your Wonderful World in the Vast ocean that is the Multiverse
May the Muses sing to you their song and help write the story you have drawn.

I would think Decay is time-based, myself.

But as you said, the decision is yours. You could possibly even combine the two aspects.

If you make it a time related effect you can easily give him all sorts of horrifying abilities magically speaking. And from the description of what it does it really does seem more like a billion years pass in an instant so all thats left is dust. Its not rotting, its aging till it falls apart.

I think you should mix the two for Shigaraki's Quirk and make it a new element as Decay is also part of death making it a Death Element. Did you get my other two reviews? I did send you some ideas through them to help your story out a bit. Love the story, but you should add auto-dress in for Hero and school related stuff to make it faster for Izuku plus have a familiar system that'll boost his states depending on their level as they level up and a pet store to by this for his little kitten.

Oh dear... Warn them now! A death battle is going down!