Well, personally to me she's my favourite video game character EVER. I played the trilogy right on every release and 100% every xeno game. KOS-MOS just really felt amazing to me. She can conjure weapons such as cannons, drills, gattling guns, shoot a huge laser from her abdomen (x buster is so amazing) that it even got cameos in other games such as tales, etc. She can do more such as you swords, hammers, she has a laser sword saber called Dragon Tooth that basically sweeps the floor and is incredibly badass. She can use pistols, powerful magic, and she's a extremely powerful weapon. In the Xenosaga games the enemies are a huge threat and without KOS-MOS to save them, everyone would have died. It's pretty crazy... in fact Shion almost dies in Xenosaga Episode I on the Woglinde to the first Gnosis attack. Other things I like about KOS-MOS are her amazing designs. My personal favourite is version 1 cause well it is classic KOS-MOS but i'm also a huge fan of version 4 since that is where all her most badass moments come from. Version 3 and 2 and Re are also fine but V3 just gets trashed early game in Episode III so I dont really find it much of a good design. I can write a whole essay about this but i'm going to keep it short and sweet before I write for hours on end. For smash, KOS-MOS would bring tons of unique options to the game. She can play rush down, zoner, defensive, and aggressive playstyles. She's not as fast as Sonic but she's really fast. Her blinding speed would allow her to perform amazing combos and coupled with her zoning capabilities with laser guns and cannons or hell anything really, she would be an incredibly powerful force to be reckoned with. Maybe she'll debuff you with Hilbert effect, or keep her cannon charged and bet the crap out of you, etc. She's great at doing that! So yeah, i'm just a really huge Xeno fan. I like so many of the characters but KOS-MOS is definitely my favourite. I'd write more as I said but it's late and well i'd go on forever.