I really love that Mortarion is trying to cleanse Barbarus it's really fitting. Mortarion likely earned a lot of respect from Big E, Mortarion doesn't like Daemons and is wary of them, also Big E likely noticed Mortarion's cleansing project.
[X] Humility. The Emperor may wage war on the stars and rule over billions, but has he ever laboured for his bread?
Big E has Resilience and Charisma in spades those aren't really in question. Also it's fitting given Mortarion's mussing about how the man who raised him would hate Mortarion living the humble life of a farmer, so it makes sense he would try and see how Big E is different.
[X] Humility. The Emperor may wage war on the stars and rule over billions, but has he ever laboured for his bread?
Big E has Resilience and Charisma in spades those aren't really in question. Also it's fitting given Mortarion's mussing about how the man who raised him would hate Mortarion living the humble life of a farmer, so it makes sense he would try and see how Big E is different.