- Very low cost of 1 SP cost at all levels (unlike most units that have a cost reduction at +3)
- High damage: effectively 480% plus chain damage at +5
- Powerful unit for PVP
- ATK buff is long lasting (6 turns)
- Strong synergy with Admiral costume (Energy Guard is based off ATK), decent synergy with Desert Flower (increases counterattack power)
- Takes advantage of current Water season buff at release
- Weak against Lecliss, a very popular tank in PVP
- Glass cannon (low base HP)
- Utility drops significantly if you don't have other costumes
Sword Queen Sylvia for PvE
No mechanics analysis is necessary because Sylvia is a simple vanilla attacker.
Sword Queen Sylvia gives us a new option for a water physical attacker (the only other 5 star option being Rafina). It is very likely that she will become necessary to obtain a high score on the upcoming fire fiend, because there is currently no other water attacker that can reach the raw damage potential of the Turn 1 Sword Queen > Turn 2 Admiral combo.
It's worth noting that although Rafina has higher damage multipliers on her skills, Rafina's base ATK is 220, whereas Sylvia's is 352. I.e. Rafina's base attack is only around 60% of Sylvia's base attack. Rafina's advantages over Sylvia are that Rafina has better AOE, better tank stats, and a DEF shred costume option.
Sword Queen Sylvia for PvP
As stated above, the ideal combo for Sylvia is Turn 1 Sword Queen > Turn 2 Admiral. This allows Sylvia to hit with two heavy AOE attacks and then become very tanky with a huge energy guard. In order to make use of this strong combo, it is recommended that Sylvia be placed away from the front lines, so that she can survive to your Turn 2, i.e. long enough to trigger Admiral.
Sylvia also opens up a lot of new great possibilities with PVP teams, because she is the only "true" 1 SP attacker to date (RH Zenith does not count as a true attacker due to her low damage). This means that in an attacking PVP team you can run 1 SP Homunculus Lathel + 1 SP Sword Queen Sylvia, and still have 3 SP to spare on a boosted ATK skill. For example (and keeping with the water theme during water season): 1 SP Homunculus Lathel + 1 SP Sword Queen Sylvia + 3 SP Steel Engine Rafina would be a strong opener with great reach. Or alternatively, 1 SP Homunculus Lathel + 1 SP White Cat Rou + 2 SP White Reaper Justia + 1 SP Sword Queen Sylvia would be another strong way to power through your opponent's opposing column, whilst leaving Rou as a sticky tank to defend Sylvia on Turn 2. These kind of set ups were simply not possible before we had Sword Queen Sylvia.
Expect to see a lot of Sword Queen Sylvia in the upcoming PVP meta.
Sword Queen Sylvia is a must-pull for any players who have already invested in Admiral Sylvia. When combined with Admiral, she makes a very powerful choice for PVP.
Sword Queen Sylvia is also very likely to be a must-pull for anyone who wants to reach the later levels of the upcoming fire fiend. Even though we don't have the details of the fire fiend's formation yet, it's obvious that Sword Queen + Admiral achieves the highest AOE damage of any water attackers released to date.
However, if you don't have the Admiral costume at high level, then the utility of Sword Queen drops a lot. Although you can pair Sword Queen with Desert Flower (free), it's not nearly as effective as having all 3 costumes. I wouldn't pull for Sword Queen unless you were prepared to also make the investment in Admiral.