The first trailer shows a battle with an army of skeletons led by a large and powerful semi-boss. Four dragon knights fight against them: Percival, Lancelot, Siegfried and Wayne. Each has its own type of weapon and a set of skills.
You can see what the knights are capable of separately and together in the second video. It shows the passage of a cooperative quest, and four players participate in it. Heroes must find and defeat the boss, the Ancient Dragon.
During the battle you can see what each of the knights specializes in. So, Lancelot can freeze enemies in front of him, Wayne intercepts the “attention” of opponents and strengthens allies, Percival causes fear in them, and Siegfried temporarily increases the attack and defense of his comrades.