Darkseb, 64 Paladin of Prexus, 927 AA's, HP 9200 ,Mana 6600, AC 1900, Self buffed only with DS pots (Skinspikes VI). No mercenary. You will find 8 (or they migth be 10) of them in a room. All are LB to me at 64.
A kill grants me 5-6% of an AA (going 100% aa and with 900+ already in pocket...).
I camp inside the room, in one corner. On logging in, will aggro the nearest one, often another one, sometimes 2 others if I'm unlucky (haven't died yet, but had to use LoH once). Once this done, next pulls will bring only one. They can go down quickly, especially if Slay Undead procs. They got 10K HP. They are magic resistant : they resist procs of my blade very often Vampire Talon, hp tap proc Planar Stun, stun proc Ward of Nife, DD Undead proc They hit me in 100-300 range approx. I resist most of their spells, except the occasional Splurt. When figthing a single opponent, without self healing, I would finish at 40-50% health. That to say there DPS meleing is not too crappy. They never resist my Deny Undead (DD Undead spell)
I clear the entire room and next small one containing 3 others before or just after first one will repop. Would say approx 15 mins repop. They never run on low health. They Summon very often if you are out of melee range (=> no escape!).
Pulling the small room : I open the door, step back, cast a non damage stun on the Lich in line of sigth. He will never summon (DD spell would make him summon instantly most of the time), and run to me. Never had 2 others come with him this way at 64. Can repeat for the next one.
One last thing to know : when figthing in a corner of the room, if they push you back into the wall, it disable your auto attack, you have to step forward to be able to attack again or cast spells. Can be very annoying when 4 on you...