That’s Sir Lora the Squirrel Knight. His story, and an opportunity to gain him as a companion, is a pre-order bonus for the Definitive Edition of Divinity: Original Sin 2. Folks that already have the regular game on PC will just get him and the Definitive Edition for free when it launches.
Other changes and additions to Divinity: Original Sin 2 coming with the Definitive Edition are outlined in this video from Larian Studios. The developers have adjusted 150,000 words in text and recorded 130,000 new spoken bits of dialog. A “story mode” difficulty is being added that combat-averse players should find even easier than the game’s current “explorer mode” option. A new tutorial area will greet novice players. Returning players will see a ton of balance and performance improvements. Finally, there’s Sir Lora and his Great Acorn apocalypse.
Like Divinity: Original Sin’s upgrade, this sequel’s Definitive Edition on PC will be a separate install. PC owners will have the option of playing both versions. The Definitive Edition launches in August.