From the looks of it...
Seems that Wyll cast it on Shadowheart.
Combat log shows Wyll casting it and Shadowheart receiving a buff (While the name is not quite right, the Shield of Faith buff is the same effect as Tyr's Protection. Shield of Faith is the default Cleric spell version of it, while Tyr's Protection and Shar's Aegis are item versions of the same spell)
