the RN has a number of method to shield allies from attack:EK using booming blade also often disincentivizes 1 enemy from moving away from him.
If he took warcaster that can be 2.
Maybe I’m missing something about the RK. RK gets size and thus can better grapple if that’s your thing. Also the larger size can help block corridors and such. He’s fairly durable too. But I’m not seeing what makes him better at tanking?
- the cloud rune
- the storm rune
- the runic shield
One could argue that the control ability of the fire rune and stone rune can also help protect allies, but that's stretching the definition.