To start, I've never changed the tanking mechanics since release. That said, I can appreciate the engine undergoes constant updates so something may have changed - I'd like to think PID has not returned in one of these as it was taken away years ago and I've not read of it elsewhere on other NPC's (As if it returned it would be a global thing).
Onto Nex's tanking modes. She has 2, that share some features:
-They both prefer to hit the furthest person away
-When she has picked a target she won't stop hunting
-She will re-check to tank every 9 seconds if she needs to re-tank
For the Ranged tank mode, she will be using her ranged attack sets and if players are all the same distance, she'll go after the person with the lowest magic defence. If she is meleeing, it is the same except she'll go after the person with the lowest crush defence.
Even if players have the same gear on, Overloads and other potion effects can modify your crush/magic defence (the real defence number is a combination of your defence level and the numbers you see on the worn equpment screen). So even if you are in the same gear... if my defence level is one less than yours, she'll likely go for me. Couple this with people having stats drained from the *cough* infection people in identical statted sets can get out of sync easily.
Further to this, in the final phase, she leeches the targets stats, so again, if overload isn't on/rebuffing you fast enough she is lkely to stick to the same person (as she is probably keeping them lowered throughout the phase)
On top of this, I made it so she isn't too predictable in terms of always doing the same thing every fight- EVERY attack she does gives her a 1/5 chance of changing to the alternate hunt mode. So if she is meleeing a player, you can expect within 5 hits that she'll start using her ranged attack sets for that phase.(So you can't just try and tank her melee all the way).
Also, players who stand on her too long will have overload drained and their stats subbed by 1 - again making that person out of sync with the team and thus a target on the re-hunt.
