That being said, which sidekick do you think is the most useful to invest in and will likely remain useful? Excluding Lumino as I tend to already play characters that can heal.
I'm a little late in responding but I regularly run with Treacherose and Shadow. The monoelement part of Shadow is a bit restrictive I guess but if he's a part of your regular team it's easy to work around it (i.e. if he's fire simply make him the main fire DD and everyone else goes for the stuff that's weak against other elems).
But I like them both together since, they make a nice tank + DD combo, and you can use both to MP steal. And Shadow has his 4AP skill for getting out of lock easily. I love them. They make boss fights so much faster imo.
Aside from them Trank is also immensely popular and will likely remain so for a while. Just give him a bunch of hp runes for an insane hp pool. 8D
This post has been edited by ennieeee - February 26, 2015, 23:54:53.