Kindred Companion

You have a loyal companion who is a full character created by you under the same rules as your own character. Work with your DM on the exact nature of the bond, any shared secrets or goals, and how the companion will be roleplayed.

When you select this background, you create your companion as a full character using exactly the same character-creation methods and options available to you (the same ability-score generation method, the same available races, classes, subclasses, feats, equipment rules, and so on that your table is using). The companion also has this background. You write their backstory (including how the two of you met and why the bond exists), choose their personality, and decide their mechanical build. The DM controls the companion in play: their actions, tactics, dialogue, and decisions. The companion is loyal to you and generally acts in support of you and the party, unless you treat them in a way that would reasonably cause them to dislike, resent, distrust, or abandon you (repeated cruelty, betrayal, constant disregard of their goals or wishes, endangering them without care, and so on). The DM decides when the bond is strained or broken and what the consequences are.

The companion gains levels (and the corresponding benefits) at the same time you do, advancing in lockstep with you.