I picked this game up in the Steam sale and I am 100% ignorant of everything in it.
I don’t really like making lots of characters, I tend to try and make one character and invest a lot of time and effort into min/maxing and doing everything I can on that one character.
I like rifles and I like the look of the Hellhound. Is there any potential viable build around those two things that can do more or less everything in the game? Like I said, I know nothing about this game, so I don’t even know where to start in terms of trying to come up with my own build around these two things.
And I would absolutely hate to start playing through the game only to get to a point and realize such a build wouldn’t work and need to start over.
Unfortunately, builds with pets that don’t focus hard on pets and pet bonuses usually end up being (at best) OK but not great at damage-dealing with the player, and poor at pet-focused play. Jack of all trades = master of none. You can probably finish the game with a hybrid pet build, but you will struggle with harder content (if you’re even able to tackle it at all).
I would seriously suggest against it as your first char. Your gameplay experience will be greatly improved if you make a strong first char that can farm quickly, you can use him then to farm for specific items that allow you to make gimmicky chars.
Start with either a Conjurer summoner (all pet damage passives, Hellhound, Briarthorn and bird, all constellations that focus on pets, pretty straight-forward), a Cadence build (either Soldier+Occultist or Soldier+Demolitionist, focus on physical damage, max Cadence, Deadly Momentum and all the passives and shield skills, also straight-forward) or Panetti’s caster (Arcanist+Soldier is good when you don’t have all the high end gear, Arcanist+Demolitionist is slightly stronger when maxed out, max out your PRM, Distortion and Proliferation, then all the casting passives with 1 point into spells like Mirror and Flash Freeze to help you survive, slightly trickier to build but has the advantage of being ranged).
All of these chars are simple enough (beat up things, shoot things or watch a movie on alt-tab while pets massacre everything) and don’t need specific items to work. You can then use your first char to farm items for other, more item-dependent chars.
Probably one of the stronger builds in game. The hellhound has a very strong aura that buffs fire and chaos damage - and we can build around that. This will mean however that the hound itself is going to be very weak (and die a lot), its only purpose really is to provide with the aura. As Tycho pointed out - either its maximum pets (and then a lot of pets), or maximum on the player character.