Sentinels of the Multiverse is a great game which understands how to make co-op fun. However where SotM understands how card games work and makes decisions from there, The Cauldron understands how SotM works and adds to and improves the base formula. This set is worth a buy if you love Sentinels. Now let's talk about why The Knight is a great hero
If Legacy is Superman, then The Knight is Captain America (and they are). But where Legacy is more support and you sometimes attack, The Knight is instead a tank. He has several cards that redirect damage, either to himself or to his armor, and cards that increase his own or his ally's attack and defense. His main cards are his sword and shield, which he has multiple copies of but only 2 can be out at a time, letting you choose between the classic sword and shield, or a great tank with 2 shields or duel-wield swords to deal extra damage
His main strength is he can tank very well and recover easily from destruction effects, and has several cards that lets him draw more. But his weakness is he can't attack as regularily as he can recover, so you might get annoyed if you're an aggressive player. Additionally if all you draw are more support cards, you might just be sitting there all game tanking with no bite. That said when he does attack, he can do a lot of damage with all his attack buffs out
Overall the Knight is a great defender and a solid attacker when needbe. While his consistency is a little lacking, he is a stalwart champion who will defend all in his realm.
[4 of 5 Stars!]