Kharn traded an eye to see every turn of the maze at once. He does not chase - he already knows exactly where you'll be, and the tunnels never surprise him twice.
The Cornered mark moves to the next-nearest enemy and his gore charge lands automatically on them - no prior mark/curse in this bestiary forces an unmissable attack.
His epic spell answers by summoning the round-1 ot2_dknight blueprint, the same illusory guardian Kessandra Vorn's Dragon Knight (round 8) calls.
The Outer Tunnels' real ceiling was Perrin Ashgrave at CR14 (round 8); Kharn is pitched one notch above at CR15, into 4 of the area's remaining Sparky slots.
He is the bestiary's first Eye of Gruumsh - reflavored here as a labyrinth-cult "Eye" bound to this maze rather than an orc-Gruumsh cultist, the same reflavor convention already used for Alienist and Force Missile Mage before it. Cloned from red_minotaur.
Real Epic Spell: Dragon Knight (id 638/875) - The Outer Tunnels' existing boss (Perrin) already used Mage Armor, so Dragon Knight went here, reusing the exact same ot2_dknight summon target Kessandra's copy of the spell calls.