Any unit charged by a unit of Winged Lancers with a Unit Strength of 5 or more must take a Panic test, as if it had been charged in the flank whilst engaged to the front.
If an Empire army does not take a Kislev allies contingent, it may instead take a single unit of the Gryphon Legion as a Rare unit. In this case, the unit is not counted as an allies unit and is treated as part of the army just like any Empire unit.