Phase is first seen at the Guildhall, working as a mercenary for the Guild and guarding the Guildhall in the event of a potential attack by the Stone Lord. He is not blind to Nine-Fingers Keene looking down upon him and the rest of the Zhentarim, but despite this, he is certain that the guildmaster would nonetheless be glad to have him once the Stone Lord attacks[1], and is eager to take the fight to the Stone Lord[2].
Phase will stand guard at X: -40 Y: 738, occasionally chatting with Slick Inatra whenever the latter stops by. In fact, he is often chastised by her for his lack of hygiene and his tendencies for placing bets[3]. He also seems completely unaware of the Zhents' true purpose at the Guildhall.
Battle for the Guildhall
When Roah Moonglow, Boss Friol, or Trinoda attempts to take over the Guildhall, Phase will join the fight alongside his Zhentarim allies against the Guild. Siding against the Zhentarim will end in Phase's demise, or in his disappearance if he's knocked out.
Provided the party aids the Zhentarim win the battle, and he survives the fight in Guildhall, Phase will guard the door leading into the guildmaster's office.
Deal extra damage to a foe you have Advantage against. Also works if you have an ally within 1.5 m / 5 ft of the target and you don't have Disadvantage.
If sided with, Phase is one of the most powerful Zhents during the battle despite his low damage output, as much of the Zhents' survival during their encounter with the Guild rest on Phase being able to stun their enemies' biggest damage-dealers.
According to Slick Inatra, Phase has questionable hygiene, and sleeps in his uniform.
References
↑"Keene might look down on the Zhentarim, but she'll be glad of us once the Stone Lord comes knocking."
↑"Dialogue with Slick Inatra: "What are we waiting for, Inatra? If we're meant to fight this Stone Lord, then let's bloody be about it." - Phase "See my uniform, Phase? It's nicer than yours, agreed? And not just because I don't sleep in it. That's because I outrank you. So when I say that I haven't even been told our orders yet, I want you to believe me." - Slick Inatra "Yes. Sergeant." - Phase "I'd also like you to bathe sometime this tenday." "Yes, sergeant."
↑"Dialogue with Slick Inatra: "The locals going to kick us out, sergeant?" - Phase "Just you, Phase. You rob the place of its glamour." - Slick Inatra "No loss. Last time I was here they had dice, blood-bouts, the works. Now it's just a lot of sulking pickpockets." "Those sulks are paying us, Phase. So chin up, make your coin, and you can lose it somewhere else. Aye?"