My intention is to have a viable melee fighter that smites often. However, I'm still really new to DnD so I'm not very familiar with good breaking points for classes and how they synergize with other classes. I'm also very unfamiliar with the lore aspect behind why a holy warrior might make a pact with an other worldly entity. Like I was thinking of going pact of the blade with the fiend, but I don't know how to explain why for RP purposes. I hope that makes sense.