hi Keith, was wondering about the Forge adept & i have noticed that the 9th level ability is just a Crusader’s mantle spell that you can change the element of, and that half of the level 15 ability is just the Defender from the Dungeon Masters guide
Was this on purpose? Yes. The versatility of Runes of War is a central part of the idea – that you can choose the damage type to target vulnerabilities – and you can use the feature a number of times equal to your Intelligence modifier each long rest. It requires concentration, but no spell slot.

— Keith Baker (@HellcowKeith) August 4, 2020