Both DMage and HElf are powerful casting characters. They can be melee-invincible if you have master-level shield lore. With a few good amulets they can be DOT-invincible. All there's left is spell-based damage that can be reduced a bit by DM's toughness and some mitigation gears or countered by HE's master level constitution. Their CAs are powerful especially for the mentalism DM and icy-HE so you have lots things going for you if you build them right.