Thou Shalt Not Pass
Night might have alot of rituals, that you can cast but the Winter equivalent, lets you influence battles and potentially wars by yourself. It’s not as versatile, but it deals with threats.
So with fronts against the Druj and the Vallorn at the moment this probably isn’t useless.
3 Warding Rituals, 1 Territory Curse and Pakanans, Wisdom.
Sorin’s Rite of Agony (+1, also the roleplaying effect seems to fit well with the build as a whole “You are painfully aware of the dangers that threaten you and those you care about. You feel an urge to prepare for those dangers, and to ensure that you have sufficient resources to overcome them.”)
Archmage of Winter’s Staff (+2 Lore) (Because honestly as a solo player blagging the Archmage’s Staff to stop X horde, might be easier than having your own :p.)
Winter Potions (+ 1 Lore for one ritual)
Enough Warding sticks that you need someone else to carry them.
Possibly something to bring you above 1 hit