Undead lull line, does cha affect it?
 

When I play my nec it seems like the undead lull line isn't very useful because I get so many critical resists on it. Incidentally my cha is very low, probably 25-35. Is my low cha responsible? The check says magic (0) on the wiki, so it should stick on things sometimes...

When you are 55+ undead lull works very well.

I don't know and don't think anything but level diff, RNG and probably target MR plays a role.

I have had the exact opposite experience. Lull is based on charisma, regardless of class. Necros traditionally will have horrific cha. I would say on my 55 necro about 8/10 Rest the Dead are crit resists.

Your low Cha is responsible. You'll need to get a cha gear set together if you want lulls to work reliably especilally when trying to lull mobs closer to your level.

Lulling mobs close to your levels is indeed hard, I was speaking more of calming your way thru HS to CR etc.