Updated for Empire of Glass. Most of the deck stayed in rotation and now even more Ultimate and Mandrake interactions. Also another source of giving Charge to Broti from Speed Grafter.
Synergies are with Broti and Merriest Mandrake. Early Mandrakes and Veteran Strategists draw cards, fix influence, and play defense. They also eat up a lot of early removal to make way for Rolant and Diana. Dropping Broti on turn 1 followed by Mandrakes and Strategists can punish some slow starts.
By no means a competitive deck, but there are some fun wins to be had getting Diana or even Talir to ultimate early thanks to Mandrake.
Praxis Arcanum feels like a weird card to include, but it can be well protected long enough to get Talir and the spells work well with Broti. Buffing a unit's toughness can give it +4 attack with Broti, and giving Broti charge lets you swing with a bunch of 0/4s out of no where.
Important note about Broti interactions: If Broti is attacking, and he or any other attacking units take damage before they deal damage themselves, their attack strength will be lowered to reflect damage just taken to health. (I think this is different from how this kind of effect works in MtG) Example: Broti is attacking and becomes a 3/3. Opponent casts Blazing Salvo on Broti for 2 damage. Broti will then be a 1/1.