Keeper of the old secrets

There are ancient secrets that are held by the gods, which contain immense power, your life is dedicated to protecting these texts. They are typically contained in powerful tomes and are scattered around the planes, usually carried by mysterious adventurers or protected by great constructs like the ruby dragon and the obsidian golem.

Secrets

You can choose three spells from any class spell lists and learn them without them counting against the number of known spells. Also, you have proficiency in medium armour and spears, can cast spells in medium armour and while having two hands full, and can use spears as arcane focuses. 

Petrification incantation

You learn an incantation that petrifies one creature you can see, this creature must succed on a your level+5 DC wisdom check or be petrified. This feature can be used every time you expend one spell slot of 1st level.

Improved secrets

You know all languages and have truesight. Additionally, you have advantage on wisdom ability checks.

Steel will

You are immune to being charmed and frightened, and  gain one feat of your choice.

Ancient power

Once per short rest, you can roll a d10 and recover a spell slot of that level, you can add your proficiency bonus after seeing the result, the roll cannot be made over 10. On a 10, you can choose the result you want.