How would HP be the same at the end? If i start with 18 CON i have +4 on every level plus at level 4 i would boost it up to 20 so i would have +5 for the rest of the game (until Barbarian level 20).
I already talked to DM in another game about 2d6 vs 1d12 and he said crit would be 5d6 or 3d12 if you're Half-Orc.
I'm already planning on going Bear totem Barbarian because i really like that damage reduction for other things. Also i was already going to take those 3 top feats you suggested, i will look into the rest because i haven't checked the unearthed arcana ones.
So start with 19 STR, 16 CON Fighter and at level 4 take some feat for +1 STR and at level 6 take GWM then start and finish Barbarian and return to Fighter?
Oh i also forgot to mention, we have a rule that if you have a shield in hand you have +2AC infront and if you have it on your back you have +2AC from the rear, so i'm gonna have a shield on my back for the whole game and never use it probably just for the extra AC and it doesn't interfere with Unarmored defense.
Is it really better to get that additional +2 STR and CON than getting more ASI/Feats, Extra attacks and another Action surge?
By the way i really like this build of yours if you haven't noticed already
Somebody correct me if I'm wrong, but I'm pretty sure that when you add to your Con score through ASI or magic means, it retroactively adds to your current levels as well. If you add +2 to Con at level 8, you'll get that extra +1 hit point for each level 1-7.
I would stick with the Greataxe then.
It's tough deciding on the secondary feats. It really just depends on what YOU want to do with this build. After the 3 obvious feats and maxing Str, I would concentrate on pumping Dex and Con depending on if you plan on using armor and for how long. Gonna use heavy armor? You can get away with taking a bunch of feats first before the Dex/Con boosts. Not planning on using armor after taking Barb levels? You'll want to get those Dex/Con scores up pretty fast. I wouldn't be too concerned with hit points. I don't think it'll be too much of a factor considering your damage resistance, your racial ability, and things like second wind, relentless rage feature, etc...
Lets re-evaluate the potential feats. You can choose 3 of these-
Alert - +5 to Initiative is big for any character. Damage resistance only works while raging so getting blasted before you can rage up is not good. The not getting surprised is a bit redundant with a Barb feature, but the not giving up advantage from a hidden character is nice.
Mobile - +10 to speed is nice. Stacks with your 5th level Barbarian speed bonus. Not provoking AoO is also good. Guess it depends on how mobile you like to be on the battlefield. I personally almost never move around much after getting locked down with an enemy so AoO are usually not a big deal for me anyway. Ignoring difficult terrain is nice when you need it.
Tough - adds +2 hp per level. Self explanatory. You probably won't NEED it, but it's nice to have.
Fell Handed - +1 to attack helps negate GWM's -5 so that's good. The 2nd feature relies on you having disadvantage, which you'll never have, and the 3rd feature requires you to use the Help action which you're never going to do so I think I would probably not consider this one.
Orcish Aggression - Do you need and/or will you use this extra mobility? Is this how you want to be spending your bonus action? Don't get me wrong. It's a strong feature, but does it fit the playing style you are after? I think I would only consider if I planned on combining it with Mage Slayer. Even without Mobile, you'd be able to Dash for 100ft, then bonus action for 50ft more towards the enemy Wizard. Then beat him down when he tries to cast a spell. This combo can be a game changer considering at high levels, parties typically have more trouble with blasty mage type characters like Wiz/Sorc npcs and Liches and such. Remember failing Wis saves is your biggest weakness.
Mage Slayer - Is this something you want your guy to be able to do? It's a strong feat, and it helps shore up your lone weakness in combat, but does it fit your concept? Orcish Aggression is not mandatory with this, just makes it a lot better IMO.
Savage Attacker - Honestly this is nothing but a luxury. I don't think I would consider it. Way too many other better choices.
You can also pick one of these half feats-
Resilient(Wis) - Again, failing Wis saves is going to be your biggest weakness. It doesn't matter if your Str and AC are both 30, a simple Hold Person spell will TKO you if you can't pass a Wis save. This has happened to my Barbarian more than once. It sucks. I would seriously consider this. You could potentially take +1 to Str and Wis at level 4 and add this later on down the road and end up with a 14 Wis plus save prof.
Athlete - +1 to Str and pure fluff. Would you even use this fluff? I think I'd pass.
Brawny - Doubling your already doubled carrying capacity sounds fun, but would it even come into play? Sounds epic if you plan on grappling. (my barb was a big grappler). You can double Athletic skill checks which is nice, but at upper Barb levels, you'll be able to skip the roll and just take the 20/24. Also +1 to Str.
Durable - Not quite as good as I originally thought. +1 to Con and you can heal a minimum of twice your Con mod with your hit die. That would be a minimum of 14 with a 24 Con which sounds amazing until you realize that the minimum you gain without this feat is still 8 and the max is 19. Sadly, that averages out to 14 anyway. This feat is actually better on the smaller hit die characters. Pass.
Orcish Fury - Choose +1 to Str or Con, Immediately make an attack when you use your Relentless Endurance. Strong, but will compete with your Sentinel Reaction attack. Also a bonus once per rest extra damage die. Ask your DM if you choose to use it on a crit, will it be an extra 2d12? or just the one. This is a pretty strong overall feat IMO. Would probably debate between this or Resilient.
Again, it all depends on what you want your character to be able to do. You can make your strengths stronger or shore up some weaknesses. Either way, it's going to be a ridiculous character.
It's totally up to you which class's capstone you want to hit first. Both are great. Like I said, the Barbarian class is going to be more fun to play. If you want the most attacks as fast as possible, go Fighter 6, Barb 5, Fighter to 11, then Barb to 20, and the Fighter to 20. Are you really starting at level 1? How quickly will you be leveling?
