Notes from author
I searched for some Havel builds but didn't really find one that I liked, so I made my own variation. The 10 dex are for the usage of the Dragon Greatsword, redistribute those 2 points to vit if you don't want it. Look out for other 50 str weapons, they might be useful.
This build can easily be changed to a Paladin Leeroy, 50 str and 30 fth do the trick. For that, you can change the miracles to something like Wrath of the Gods and Great Heal.
Also, Green Blossoms are highly recommended for an offensive phase, as opposed to an (initial) defensive phase with GMB.
As a little trivia thingy, I think that Sunlight Blade would make sense for Havel to have since his plot to overthrow the Gods (which is a big fan theory) and his defense against magic would make him a good candidate for defeating Gwyndolin and finding the miracle.