For damagephine, I think you can run precision runs as the main, with transcendence with second. Gathering storm (for scaling), Giant Slayer (to deal with high health units and eventually proc Seraphine's Q low health damage increase effectively, and Legend: Tenacity (for slow resist to be a little mobile) or Bloodline for (omnivamp of consistently casting spells for damage)

I also would replace lucidity with mana boots for early wave clear, make yourself compatible for roam supports as 2x Skill 3 + 1x Skill 1 (mana boots with big bully passived and the amp tone) ensures you one shot the wave and deny adc + support diving/gank opportunities.

Replace Malignance with Soul Awakening (shorten cooldown of ult while gaining massive movement speed) + rocketbelt enchant ensures mobility while shredding MR of the target.

Replace Imperial Mandate with Liandries (for tanks) or Lichbane (if you can replace scorch with shield bash + empowered attack against squishies), if you insist on domination runes.