The Beginning After the End, Vol. 2 (comic)

Reincarnated king-turned-kid Arthur Leywin and his travel companions have been ambushed by bandits, and Art only has one thing on his mind: protect his family. But he soon realizes his strong mana core alone might not be enough to get everyone out of danger—even with the knowledge and experience from his old life, this new world is a formidable place. And when mythical creatures and slave traders are thrown into the mix, Art's going to have to pull out all the stops if he wants to stand his ground!

Volume 2 of The Beginning After the End manga series by Erin Hickman.