Lei Dang.

Lei Dang, an Envoy of the Order, is a tall, squared-shouldered man whose severed arm ends in a stump carrying a cannon shaped like a tiger.

He crosses the player's path on two occasions. Within Pangzhen, he is the NPC responsible for mending the Flaming Mane Phantom Edge. He then comes back as a boss at the far side of Mirage Estate, where the battle feels like a duel with an old friend and not a clash with a stranger.

Opening with the Tiger Cannon, he later puts it aside and switches to punches, a smash into the floor and a bounding strike. You get the Tiger Cannon for beating him, together with the achievement All Return to Dust.

Losing the arm

Soul saved Lei Dang when a mission cost him his right arm. Afterward he mounted a hand cannon shaped like a tiger on the stump; charging it makes a roar like a tiger's.

Mending Things at Jingyang Hall

Once Flame, the Mask-Bound Lion Dance Grandmaster, has fallen, Soul carries the Dormant Flaming Mane to Lei Dang at Jingyang Hall. Lei Dang restores it as the Flaming Mane, a Phantom Edge able to burn through dense vines.

Spoilers: how Mirage Estate was reached

Zuo Shang, the new Shadow Sovereign, dispatched Lei Dang to Pangzhen. After the earlier Sovereign Mu was killed and Soul turned out to be the murderer, Lei Dang was supposed to arrest Soul immediately. Rather than do so, he hesitated and pointed Soul toward a route to Mirage Estate.

Only afterward did he learn the truth: the substance he swallowed was the real Trickster's medicine, and from the very start Leng Tu's whole plot had snared everyone. His final desire is to face his old friend in another fight.

Duel at Mirage Estate

Close to the Perfect Vessel Pond bell, at the far end of Mirage Estate, he is waiting. Two phases make up the battle; he enters the second, as the One-Armed Tiger, when he throws his cannon away.

Boss battle at Mirage Estate

In the Tiger Cannon stage he fires the charged cannon, which gives a tiger's roar and delivers heavy firepower. When he throws it away, his one-armed style takes over: mountain-rattling punches, a ground slam that unbalances opponents and leaves them open, and a thunderous leap that can only be dodged with the help of the terrain.

Base HP stands at 9,000 for the Tiger Cannon form and 10,000 for the One-Armed Tiger. Ice hurts both forms. Lightning also hurts the Tiger Cannon form, while Poison also hurts the One-Armed Tiger form. Fire and Water are resisted by both.

The Envoy's trademark weapon is the Tiger Cannon. Once Lei Dang is beaten, the player receives it as a Phantom Edge that shoots strong ranged attacks and shatters marked stone barriers, opening hidden areas like the wall south of Weeping Creek Long Pillar and the tunnel at Cliffside Lodge.

Taken from his voice acting

“Finish this drink... and our friendship ends here!”

A line the game's voice cast gives to Lei Dang.

“a charge from my Tiger Cannon will reignite its flame.”

A line the game's voice cast gives to Lei Dang.