I fixed Halphax a while back; how is he now?

Behold, a new Vestige! (you can format it proper; I suck at formatting)

Spoiler: Marchosias, King of Killers
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Marchosias
King of Killers
7th Level vestige
DC: 17
Sign: Your eyes grow a red-orange color.
Manifestation: Marchosias appears with a bloodcurdling scream in an explosion of fire and black smoke. Though much of the smoke curls away, some remains and slowly coalesces to form a human figure. Marchosias appears as a king with body and raiment composed of swirling smoke and cinders. He wears a crown of fire, beneath which gleam two glowing, hot coals where his eyes should be. Marchosias wields a scepter of flames, and a sword of hot ash is belted to his hip. For a moment, he seems exhausted by the rigors of his arrival, standing with his shoulders slumped and his head bowed. After a moment, he raises his gaze to his summoner and stands straight and tall, adopting an imperious posture.
Granted Abilities:
Death Attack: If you spend 3 rounds of combat studying a target (and taking no other actions), you can make a special melee attack against it. When you do so, you either choose paralyzed or dead. If you hit with your attack, they must make a Constitution saving throw (DC 8+your proficiency bonus+your Charisma modifier) or die (if you chose dead) or be paralyzed for 1d6+1 rounds (if you chose paralyzed). If they succeed the saving throw, the attack is a normal attack, except it deals extra damage equal to the sneak attack damage of a rouge half of your binder level.
Fiery Retribution: You deal an extra 3d6 fire damage to opponents who can situationally deal extra damage (paladin's Divine Smite, rouge's Sneak Attack, etc.). If you deal this damage with a ranged attack, it only comes into effect when the target is within 30 feet of you.
Smoke Form: You gain the ability to use the gaseous form spell once per short rest, except you can remain gaseous for as long as you wish. You lose all granted abilities of all bound vestiges for the duration, but you do not expel the vestiges or lose the ability to remain in gaseous form. Since you lose death attack, you cannot use this time to study a target.
Silent but Sure: You gain your proficiency bonus as a bonus to all Stealth and Perception checks.
PACT INFORMATION: Marchosias seems to have appeared as a vestige quite recently—in fact, only a short time before Dahlver-Nar did. In life, Marchosias was a human who brought death to others. His favorite targets were other assassins and murderers, but this choice of foes had nothing to do with morals. Despicably evil, Marchosias was obsessed with improving his skill as a killer, and ending the lives of other professional slayers seemed the best challenge he could undertake. When at last Marchosias met his death, his soul traveled to the Nine Hells. The devils gleefully accepted his powerful spirit, but others there took note of his arrival and were not pleased. The spirits of hundreds of thugs, slaughterers, executioners, and assassins banded together and rebelled against their devilish captors—intending not to escape or take control, but to attack Marchosias. Although the devils were loath to allow such lawlessness, they let the souls of the damned fight it out, thinking to step in and punish all the spirits when the battle was over. Marchosias fought well, but he could not prevail against so many foes at once, and he fell under the onslaught. When the devils pulled back the attackers, nothing was left—Marchosias’s soul had been torn to pieces.