>>719212178
Most act like normal (New Heroes, Seasonals, Legends, Mythics) but they also introduced Emblem units.
Emblems have a separate Engage function that allows you to add OP buffs to your other units' Special skill, like reduced cooldown, damage based on speed, etc. Sigurd also increases move range and gives canto, Celica lets you warp five tiles away, Lyn lets you snipe five tiles away, etc.
Unsurprisingly, they're the only popular Engage units aside from the two Ivy units they made years ago.