Heroic Bloodline

Many years ago, long before your time, there was a great hero. This hero did innumerable great deeds, and went down in history as a hero of legend. However, time causes all memories to fade, and this great hero is largely forgotten these days. Most remaining records of this hero lie with your family, a direct line of ancestry to the hero. As a thank you from the gods for this hero's help, they were bestowed a blessing. However, there was not much that could be done with this blessing to help the hero, with how incredible they already were. So the blessing was that, in generations, when the world was in need, the hero's descendant would awaken with great power, and receive aid from the past hero's soul. That descendant to awaken with great power? Yeah, in case I wasn't clear, that's you. This descendant would possess the exact appearance of the hero, as well as the hero's personality, to ensure that the power is used as intended. (Please note, for story purposes, you're like the hero, but as far as character creation goes, it's the other way around. The hero is like your character. Also, if you want this subclass as an evil character, I never specified WHAT gods gave the blessing, and history is written by the victor.) 

Hero's Kindness

The power of your bloodline flows out and forms into a force to protect those close to you. Whenever you cast a spell, gain the option to grant one creature of your choice +1 AC until the start of their next turn. At third level, you can spend sorcery points to grant additional creatures this buff, the amount being proportional to the number of sorcery points expended.

Hero's Divinity

You know the Celestial language, and you know the spell Cure Wounds automatically, without having to learn it or it taking up a spot in your known spells. Your bloodline's divine connections also grant you advantage on Religion checks and on saving throws and attack rolls against undead.

Hero's Strategy

The innate understanding of battle granted by your ancestor's blessing grants you superhuman planning. As an action on your turn, you can use this feature to increase the AC of yourself and one ally that can move and can hear and understand you by 1. So long as you are within 10 feet of each other, this boost is increased to 2. This boost lasts until the start of your next turn. Even if you otherwise would not get an action, you can still use this ability, so long as you can see and move, even if that movement is limited. For example, you can still use this if restrained, but not if stunned. (So you understand how this works, in world, you are predicting the next few seconds of battle as it pertains to you and your chosen ally, then calling out to them the enemy's next move in regards to them. And, if within 10 feet, you are working as a united front in each others defense.) If an enemy you did not see attacks or otherwise directly changes the situation unpredictably, this bonus AC is immediately lost.

Hero's Guidance

Your ancestral bonds continue to grow, and finally, your ancestor can assist you in person. At any time, you can summon the ancient hero's spirit to assist you. They can also appear on their own, if they determine that you need help. Dismissal of the spirit works similarly. They can speak and think, and are extremely similar to you. They cannot interact with the physical world, but will otherwise assist you in any way. You control the spirit and how they behave (including if and when they summon themselves), but the DM determines what they do or do not know, and what their past is like. Some ways you can have them help is locating things, sharing history, pointing out hidden things, and making perception checks separately from you but on your behalf. Whether or not the spirit can do something not mentioned here is up to the DM. The spirit is invisible and inaudible to everyone but you unless you decide to allow someone to see and/or hear them, or they are themselves a spiritual being. Their initiative in combat is 2 less than yours, and they have the same speed as you. They can move vertically freely, but it uses movement at the same rate as horizontal movement. They can take up the same space as any non-spiritual entity without consequence, and vice versa.

Hero's Unity

Your ancestor's soul is truly bonded with your own, and you have become one with each other. By spending two sorcery points, you can use the turn of the spirit to have them possess you, allowing the hero spirit's turn to become an additional turn for you. If an individual is of the same alignment as you, you can spend 5 points to have the spirit possess them, and use the spirit's turn to control them instead. Possession of yourself lasts 5 of the spirit's turns before you have to spend another 2 points, but possession of an ally only lasts one turn before the cost is reincurred. Possessed individuals, including yourself, still take their turns as normal, you just take an extra turn with them using the spirit. The spirit has to enter the space of an individual to possess them.