Templar used to be annoying rare you’d face on some waves due to his annoying choice to provoke your champs and place block damage. Otherwise he became food for your more powerful epic and legendary champions. That was until the release of Bommal, the Dreadhorn as part of the new bosses in Rotation 3 of Doom Tower.
Templar’s unique ability to self-buff with Block Damage meant you could avoid the dreadbomb damage and therefore allow him to solo the boss (although you most likely will need to manual). You’ll need to run your Templar in both Regeneration and Immortal gear with 70k HP and around 200 speed but this can achieve even the top difficulty with patience.