I'm joining a campaign that the players are struggling immensely on. At level 6, they almost got wiped by 4 flameskulls with reduced AC. They are going to level 14. My current plan is Oath of the ancient paladin 11/ totem barbarian 3. I'm going to try to get unarmored defense higher than tortle base AC, and i'm thinking of a ring of psychic resistance, a defender. a shield of the cavalier, and an animated shield. 

Are you using ‘14 rules or ‘24? Under 24, smite is a spell, which won’t work well with barbarian raging.

There is 2 ideas with this build. one is going more on offense, which is when I would cast spells. Defense would be when I rage, for Resistance against all damage except psychic for at least 1 round. Using 24' rules.

Quote from NemesisO7 >>

I'm joining a campaign that the players are struggling immensely on. At level 6, they almost got wiped by 4 flameskulls with reduced AC. They are going to level 14. My current plan is Oath of the ancient paladin 11/ totem barbarian 3. I'm going to try to get unarmored defense higher than tortle base AC, and i'm thinking of a ring of psychic resistance, a defender. a shield of the cavalier, and an animated shield. terraria full game download

 Solid plan. Ancients' aura and Bear totem will make you incredibly durable. Consider Sentinel to lock down threats and protect your struggling party members.