the ultimate arts in AA and AO are drastically different in how they work
in AO, it will basically just be a bigger version of a regular spell with more startup time and endlag, but in exchange deals significantly more damage.
I think each spell has an ultimate art, but you’ll need to invest in the magic stat in order to use all of them, because each one has a certain minimum stat total quota you need to reach to be able to toggle the option on a certain spell.
for example the ultimate art quota for a dash spell is higher than the quota for a blast spell.