So I run some tables and want to make a boss who has a character statblock,

I was thinking of an artillerist artificer, level 6, sea-elf, fisher background for lore reasons and sharpshooter.

set up: players on a ship, cannon takes out ship, they have to get to close range to fight artificer.

all I need is help with spells he will level up as the characters level up so mostly aggressive although he will get shield.

Spells at any level for artificer artillerist please.

Artificer is a half caster and their spells are meh.

They use their spells for support, buffs, etc. But their main mode of inflicting damage is 

Armorer: special weapins built into armor

Battle smith: their pet

Artillerist: their arcane cannon

Alchemist: nope