I took Anomen with me, but only for a very short time in my new game. I wanted to just have him for a little extra muscle while trying to pluck Keldorn out of the sewers.
When I got down there, I had Anomen cast Spiritual Hammer to help deal with some of the monsters. When I got to Keldorn, it was time to dismiss Anomen, and I did just that, with the spell still active.
Anyway, I went to pick him up a few days later in the Copper Coronet, and he still had the SH active! I kept him in my party for about an hour of real time, I tried sleeping with him in the party, and the spell still never went away! I guess I could try casting "Dispel Magic," but I really don't care either way. As a matter of fact, it looks pretty cool!
I'll pick him up after Spellhold and see what's up. After all, I wouldn't want him spending the rest of his days in the Copper Coronet without ever learning that his sister was murdered!