In a way the easiest champion of the Cloaks to use because she is so inexpensive. Dagger can go from good to extremely good, her cheap cost + Sly + 3 damage is already good enough, giving you decent stats and all the advantages of Sly. But when she can use and abuse Backstab, she can get crazy, especially with Out of Shadows.
Dagger can create the triple backstab to a summoner that works like this:
Get Dagger behind the target and attack, Sly with a Rustside Bandit and attack, Sly the Bandit for Vlox that has copied Dagger and attack. And you now have 10 dice on the enemy summoner. This probably will require Moto Boots or the help of a Gunner or Out of Shadows if you skip the Bandit attack.
As being very good value, always try to summon Dagger, even if you don’t plan to Backstab, but for sure go for it if you can.