You can regenerate 1d4 hit points or stabilize yourself a number of times equal to half your constitution modifier rounded up (minimum of once) per long rest.

Your constitution score increases by 2 and your wisdom score increases by 1.

Ultimate abilities come in all shapes and sizes and are magical in origin. They can be things like an ultimate shield, ultimate eye or an ultimate claw. You can only choose one ultimate ability and cannot change it after the fact. Choose wisely.

Ultimate Eye.You gain advantage on all checks that rely on sight and get dark-vision equal to 60 feet

Ultimate Claw. You use your bonus action to harden and sharpen your fingers to make them as hard as steel and deal 1d6 slashing damage + your dexterity bonus.

Ultimate Shadow.  Shadow is empowered and gains these stats and https://www.dndbeyond.com/monsters/407350-ultimate-shadow it cannot be summoned if a shadow cannot be produced. Can be summoned a number of times equal to half your con modifier rounded down, is killed if it enters areas where no shadow can be produced or gets more than 30 feet away from you. You control the ultimate shadow in combat

Ultimate Shield. You use an action to harden your skin to the hardness of metal. This increases your ac by your proficiency bonus and grants you resistance to nonmagical piercing and slashing damage a number of times equal to your con modifier and cannot be equipped for more than an hour at a time.