No (and you are right not too)

In the end, you see no reason to shake hands. Neither you nor the undead are human and are not in polite society. Besides, you don't trust this creature enough to indulge its gesture.

So you remain on your side, still fenced with suspicion your tail fin firmly planted against one of the logs making up the raft and hands supporting your torso.

A wise decision in fact since the Lich grabs for you anyway

"Shocking grasp"

He incants, a nebulous blue static detonates in his hand. You manage to dodge most of it by lunging and twisting away, but it briefly grazes your chest and the shock makes you jerk back and gasp, almost falling back into the water.

The lich reaches for you again "Teather of pain". You drop and roll avoiding the spell and cursing your decision ever to deign even giving an inkling of trust to this evil untrustworthy creature.

You charge the Lich desperately from the flank and manage to knock it over on its side.

The Lich grabs your anal fin.

"Life drain" You shake briefly as energy surges down to the anal region of your fish tail and through your lower fin. The sensation is unexpectedly enrapturing. But your gills flare and your ear fins vibrate and you manage to master yourself even though the effect seems somewhat reduced outside of the water.

You throw yourself away, making sure to slap the Lich with your tail fin hard enough to push him over and make for the edge of the raft. Your chances of getting away from the squirmies are better there, than on this small space.

"Crippling Shot" You don't like the sound of that, so you turn and throw up your arm desperately. Something wet shoots out from behind you and collides with the purple magic causing it to scatter and dissipate.

You stare in astonishment.

The Lich pauses as well, staring at your wide-eyed self.

It raises a hand experimentally-

"Shards of agony."

This time you throw up both arms and a film of water covers you in a makeshift shield. The shrapnel shards of magic splatter against it harmlessly.

You stare at it and the water collapses, wetting the wood of the raft. You look up at the Lich who gazes intently back at you, tilting its horned head and eyes burning malevolently from under the shadows of its hood.

"Curious" it lifts one finger. You don't wait for it to incant but fling out a hand, an arrow of water shoots out from behind you, hitting the Lich right in one of its empty sockets.

You pause, surprised but triumphant as the Lich is sent sprawling yet again on the raft. But your triumph is short-lived.

"Arrises my creation, arise Fafnir." It intones. Seemingly fazed by your attack.

A chill goes up your spine as the words sink into you like a thousand cloying strings. Your dorsal fin perks up and your ear frills flare instinctively.

A shadow falls over you.

You look over your shoulders. Your ears droop in trepidation at the sight behind you.