The multi-form is supposed to have a weakness on the long run in terms of durability, so it makes more sense to use it for some sort of one-time surprise overwhelming rush, rather than something that stays on screen and can do its own thing.
If I struggled to the end of my determination, to the end of my way of life with my followers, if the result is ruin, then this ruin is inevitable. Grieve. Shed tears. But you cannot regret.