For 4-ER, you can consistently neutralize an attack from a weak minion every turn for the rest of the game.

Danny really wants to be a Voltron ally though, with you stacking Inspired, Sidearm and similar cards on him to amp up his power so he can start tanking hits from the villain. If you use both of those with the new Righteous Purpose, you can get him to 6 ATK and fairly consistent block the villain.

That's a high investment to get him built up there, but I suppose it's worth it to prevent all that damage.

He's very similar to Echo but I think she's usually better since she doesn't need to be down to 1HP to reach her full potential, and Protection has access to Hangar Bay to let her block multiple times. Although one advantage he has over her is that he can block for teammates in multiplayer if you need to go alter-ego, while Echo loses her protection if you switch down.