The quest Breaking The Ranks, as we are all aware, has a Dracolich, "Arricaxerxes" that wakes up during the Orc wave, and bombards the battlefield for the remainder of the quest. If you damage him at any point, he says:
(Say): Arricaxerxes says, 'Run, tiny morsels! Run! Your fear only makes me stronger!'
Followed by a DM line of:
(Dungeon Master): The Dracolich roars triumphantly and his wounds seal. Only those with true courage will be able to defeat it.
Once he's taken any damage, he fully heals himself in <1 second, and keeps repeating his "Run tiny morsels" line. The DM audio hints at some way to either get him to come down and fight, or at least stop regenerating, and I've tried greater heroism, being in a Paladin's anti-fear aura, among any spells that seem like they would bolster courage, but never seem to get a different result. This life before TRing, I decided to go in on casual with a capped wizard and toss a meteor swarm at him. This did enough damage to reduce him to <0 HP before his half-second full heal procced, and I got a couple extra dialog lines, and he actually died. His extra lines were:
(Say): Arricaxerxes says, 'Look at you! Holding on to your pitiful hope! You will beg me for death when I am done with you.'
(Say): Arricaxerxes says, 'My phylactery still exists! We will meet again!'
Note that there was no optional XP, and no extra DM lines, nor did the quest change in any way, other than no more bombardment. This makes me think that initially they had planned to make him fightable, and perhaps there was an optional geared toward stopping his regeneration and killing him for an optional, and perhaps this just was never implemented before the expansion came out, seeing as how there are extra dialog lines and he is in fact killable, there's just no objective for it. At least I got him in my Monster Manual!
Any dev comments? Was this something that just never got around to being implemented, like the Vampyr Dark Gift transformation that was planned for Ravenloft but never implemeneted, though the dialog lines for it still remain?