Character Crunch: The Onijin, The Civil Servants of the Mugen Empire

Onijin are the descendants of an oni warlord that was married by alliance into their family at the behest of the Jade Empress. They are often employed as body guards and advisors to important nobles, due to their innate abilities, and almost all onijin receive some education in the arcane either by tutor or the Imperial Mage Academy. While they are respected by the Mugen nobility, they are often feared and even persecuted by the common folk.

Ability Score Increase. Your Charisma score increases by 2 and your Strength score increases by 1.
Age. Onijin reach maturity at the same rate as humanoids until their prime and can live for up to 500 years.
Alignment. Onijin are almost always nobility and have a tendency towards lawful alignments.
Size. Onijin have builds similar to most humans and are medium sized.
Speed. Your base walking speed is 30 feet.
Dark Vision. You have the fierce eyes of an oni, especially in the dark. You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can't discern color in darkness, only shades of grey.
Elemental Resistance. You have a oni ancestor. Choose one type of oni demon (Acid, Cold, Fire, Lightning or Poison). You have resistance to the elemental damage associated with that oni ancestor and you gain a cantrip. If you choose acid, you have resistance to acid and you know the acid splash cantrip spell. If you choose lightning, you have resistance to lightning damage and you known the shocking grasp cantrip spell. If you choose poison, you have resistance to poison and you know the poison spray cantrip spell. If you choose fire, you have resistance to fire and you know the firebolt cantrip spell. If you choose cold, you have resistance to cold and you know the chilling ray cantrip spell. You use Charisma as the spellcasting ability for this cantrip.
Enlarge. For 1 minute, the onijin magically increases in size, along with anything it is wearing or carrying. While enlarged, the onijin is Large, doubles its damage dice on Strength-based weapon attacks (included in the attacks), and makes Strength Checks and Strength saving throws with advantage. If the onijin lacks the room to become Large, it attains the maximum size possible in the space available.

You regain this ability after taking a long rest.
Student of the Arcane. Onijin are almost all educated in the ways of the arcane. You gain proficiency in the Arcana skill.
Extra Languages. You can speak, read and write in common and giant.