How would you guys do a 5e barbarian 1/3rd caster subclass?

[Spacehamster]

Always liked the 3.5 book of exalted deeds prestige class "champion of Gwynharwyf" that had limited casting that could be used while raging. What type of abilities and spells would you give a home brew 5e version of this pc?

[Final Hyena]

There is this (http://www.giantitp.com/forums/showthread.php?415340-Rage-Mage-(PEACH)) and this (http://www.giantitp.com/forums/showthread.php?473508-Barbarian-Spellcasting-Primal-Path) that you could have a look at.