I really like assassins. I used to think the R'lyeh Starspawn was worthless after paralyze was fixed, but he's now my favorite. Stick a lifelong protection on him and he's great (admittedly a bit hard to come by for R'lyeh - probably a blood-1 Random Starspawn or Sage with a ring of sorcery and wizardry/empowerment to get to blood-3). Unlike the other assassins he has the luxury of being able to paralyze anything the imps can't take care of themselves. He also has the flexibility of being able to throw on resist magic, body ethereal, personal luck, astral shield, etc., as needed. Personally, I've been using Resist Magic, Body Ethereal, Fire, but that can be changed up if you know what you'll likely be facing.
Actually, my favorite assassin is an Earth Elemental, but that doesn't really count
Question 1) If someone has flying bodyguards, will they fly at the assassin or stay by the commander? My guess is that they'd stay by the commander unless the assassin started firing at him, but I haven't seen flying bodyguards in a while.
Question 2) What's your favorite assassin?