The first true and dedicated mage that you get in the game. How does she hold up? Let's find out.
Damage - Her biggest role and what she does best
Control - One control skill but it's a pretty good one
Unstable - Prevents Understudy from being controlled, a useful trait especially for a mage
Tasty - Ambush Spider bait
Reverent - Able to be revived by Angel Dragon
Physical Basic attack, magical skills
Punch Out - More than likely your first nuke skill and it's a pretty good one. It does non-elemental magical damage to a single target. It does good damage and I've seen it take out a foe all by itself, but don't rely on that.
Meteor Shower - In my opinion, the best out of Understudy's skills. This skill hits all enemies for magical damage and does about half the damage of Punch Out. This is still very respectable damage and the fact that it hits everyone makes it even better.
Hunger Pang - This is Understudy's control skill. Basically it cooks a foe, deals magical fire damage and then leaves them disabled for 3 seconds. Does about the same damage as Meteor Shower but only to one target that is randomly chosen. The control is really nice as it completely shuts down a single target, I just wish you could aim it.
Positive Energy - The first passive skill that Understudy gets and it's a good one. This grants her additional energy every time she attacks. This means Punch Out can be triggered more often for more damage. Worth investing in, but not a game changer.
Energy Shield - Understudy's Legendary skill does a good amount to help her low defenses. This skill provides a shield at the start of combat to absorb some of the starting round of attacks and let her get some shots off. In addition, every hit to the shield provides 100 energy (or 1/10th of the requirement for Punch Out). This shield expires after 10 seconds. Also works as a good block for bone dragon and void wyrm' s energy drain.
Honestly, all she needs is Ocean for the skill power, everything else is just icing on the cake. Many also use River for competitive meta use.
Brozerker - Boosts her Energy Shield a lot and can protect her with his shields, doesn't line up a lot before Understudy gets her legendary though.
Moon Drake - Provides additional energy (not that Understudy really needs it) as well as an Intellect boost via Beacon.
Groovy Druid - Good Vibrations reduces magic resist, boosting Understudy's damage and Hedging our Bets takes out shields allowing Understudy to deal damage more easily.
Water Wyrm - Adds some more control skills as well as Perfect Storm giving Understudy Magic Vamp, helping her fragility
Kraken Lord - Mostly for The Horror which reduces magic resistance
Ninja Dwarf - He seeks out high Intellect heroes, Understudy has high intellect. Also Ninja has increased magic resistance and Gun Punch knocks away some of the damage.
Ambush Spider - She's tasty, so she's eaten.
Cosmic Elf - All his silencing skills neuter Understudy's power but he doesn't deal a lot of direct damage usually.
(+) Good single target and multi-target damage
(+) Energy Shield and Positive Energy keeps her energy generation high
(+) Energy Shield helps keep her alive long enough to get some hits in
(+) Probably one of the most reliable counters for Spectral Drake
(-) Before her legendary is unlocked she is quite fragile
(-) Magic attacks don't trigger Life Drain making her even more delicate
(-) Her damage does not hold up against later heroes
(-) Since her skills are non-elemental and she has few passives, it's hard to make synergies with teammates.