Fire 
Reverb elements, who belongs to the Source Citadel faction. Their position in combat is Front.
Suen provides great healing by sacrificing her own HP. Not only that, she also applies a buff to a single ally to deal more damage with their cards. Her Ultimate also provides massive healing, Cleanse and Damage over Time (DoT).
Playstyle and Key Mechanics
Suen heals and buffs allies at the cost of her HP. While as a Healer, you can easily fit her in most teams simply for her Sustain, there are a few teams like [Ignite] or [Shadowcraft] focused teams she works in even better.
MAIN CARDS
Starting with [Neotune], this skill allows her to add healing to her [Basic Attack], which costs 13% of her current HP and can heal all allies except her. This skill can also generate a [Shadowcraft] card at a 50% chance.
Next is [Old Chapter]. This card also costs 13% of her current HP and provides [Restless] buff to one ally while also drawing one of their cards from the deck. Once this card is used or enters the Discard pile, it can also generate [Shadowcraft] at a 50% chance.
Lastly is [Purge], which instantly cleanses all allies' debuffs and restores their HP by a significant amount. A great card for Suen to keep using her skills, as they cost a surmountable amount of health.
DERIVATIVES
[Shadowcraft] - This is a spell that deals Reverb damage. After using it 13 times, it will use [Darkest Hour], which deals massive AOE damage.
Investment
Awakening investments for Suen are mostly involved with her healing. By upgrading them, you can make her use her [Basic Attacks] faster, which means she can heal faster and further buff allies' ATK once she heals them. Now let's take a look:
Awakening 1 - Each time Suen heals an ally at a certain threshold, she increases their ATK by 0.1% with a cap of 39%.
Awakening 2 - Whenever she uses any skill card of hers, she gains [Berserk], making her do basic attack faster and if [Neotune] is used, the rate of her healing is also significantly increased.
Awakening 4 - Whenever a [Shadowcraft] card is generated, you gain 0.5 cost. If other crew members in the team can also generate [Shadowcraft], it will make the cycling smoother.
Awakening 5 - Now, when using [Shadowcraft], it also deals additional damage that scales off HP and the average ATK of all Allies.
Resonance
Resonance 1 - She now randomly heals an ally every 6 seconds.
Resonance 2 - Increases her DEF whenever she gets hit. Given that she is a frontliner, you will be capped on this pretty much instantly. As a side note, her cards that cost HP also increase the DEF stacks.
Resonance 4 - Whenever [Neotune] is active, it also increases allies' Final Damage by 10% and whenever it is inactive, all allies now take 10% less damage.
Resonance 5 - At this Resonance, she just becomes more consistent with her healing by being able to heal whenever a [Shadowcraft] is used; not only that, she becomes a [Basic Attack] powerhouse by being able to stack her [Basic Attack] damage up to a maximum of 390%.
Synergies
❗ ❗ ❗ The Synergies mentioned here are merely samples. Taking their core mechanics as an example, you can use many other characters as replacements or other synergies. ❗ ❗ ❗
Margiela - Suen has tons of Purple cards, making it easier for Margiela to use her Leader skill, which requires Purple cards to be used.
Katas - She greatly buffs Katas’ card damage by buffing her with [Old Chapter].
Arina - Arina can apply [Berserk], which makes her do [Basic Attacks] faster, as mentioned earlier in her Awakening 2.
Rachel - Incredible cost generator, just helps for cards not to be stuck in hand.
Gear and Affixes
Some examples of overall good equipment choices for Suen. For specific picks, please check the respective teams.
Weapons:
UR Hook of Regret: Using [Shadowcraft] enables all subsequent [Shadowcraft] and [Darkest Hour] to deal 13% more damage. This effect stacks.
SSR Cunning Betrayal: Using [Leader Skill] has a 20% chance to generate a [Shadowcraft] at the top of your deck. The trigger rate stacks.
SSR Unbewusstes Probe: Whenever you play a Red card of cost 3 or more, random enemy receive 3% less healing. This effect stacks up to a maximum of 75%.
SR Viscera Collector MK 0: Using [Leader Skill] restores 0.4 Cost. This effect stacks.
R Mass Projector: Using [Leader Skill] increases ATK by 1.5%. This effect stacks.
R Magic Wand: Playing a Purple card has a 20% chance to restore 1 Cost. The trigger rate stacks.
Armor:
UR Cactus Plate Armor: Playing a Green card with a cost of 2 or more restores 0.5 Cost.
SSR Simulated Stars: Using [Leader Skill] restores 5% HP. This effect stacks.
SSR External Memory Matrix: Max damage taken per hit is 33% of Max HP.
SSR Healing Flak Suit: Playing a Green card restores 5% of Max HP.
SSR Black Rock Armor: Reduces wearer's final DMG taken by 10%. This effect stacks.
SSR High Dimension Construct: Generating a Black card restores 5% of Max HP. This effect stacks.
SR Resonance Fiber: When own skill card is used, restores 2% of Max HP.
Accessory:
UR Dawncloud Seal: Max Hand Size +1.
UR World Line ß Box: Draws a card whenever you encounter a wave of enemies, prioritizing wearer's skill cards.
SSR Mobius: Cards in your hand are replenished 0.25 seconds faster. This effect stacks.
SSR Divinity Seal: Gains 2 Cost at the battle's beginning. This effect stacks.
SSR Fengshui Tactical Drone: For every 8 cards used, increases ATK or DEF by 2%, up to a maximum of 50%.
SR Magic Spring: Restores 0.02 Cost per second. This effect stacks.
SR Lion Emblem: Wearer's Purple cards deal 15% more damage. This effect stacks.
Affixes
Using [Leader Skill] restores 0.2/0.3 Cost. This effect stacks.
Using [Leader Skill] restores 2/3% of own Max HP. This effect stacks.
Using [Leader Skill] increases own ATK by 0.5/1%. This effect stacks.
Increases own ATK by 1/3%. This effect stacks.
Increases own ATK by 10/30. This effect stacks.
Increases all own trigger rates by 1/5%. This effect stacks.
Playing a Red card increases own ATK by 0.2/0.5%. This effect stacks.
Increases final DMG dealt by 2/5%. This effect stacks.
Restores 0.01/0.02 Cost per second. This effect stacks.
Gains [Hyperarmor] for 1 second when using own skill cards. This effect stacks.
[Nova], [Elemental Nova], and [Supernova] deal 5/10% more damage. This effect stacks.
[Shadowcraft] deals 5/10% more damage. This effect stacks.
[Shadowcraft] heals the caster for 2/5% of the damage dealt. This effect stacks.
Playing a Purple card restores 1/1.5% HP. This effect stacks.
[Curse] dealt lasts for 1/2 seconds longer. This effect stacks.
Grants 5/15% more healing. This effect stacks.
Receives 5/15% more healing. This effect stacks.
[Injure] dealt lasts for 1/2 seconds longer. This effect stacks.
Inflicting [Wildfire] restores 0.05/0.1 Cost. This effect stacks.
[Ignite], [Blaze], [Wildfire], and [Inferno] dealt deal 5/10% more burning damage per second. This effect stacks.
[Ignite], [Blaze], [Wildfire], and [Inferno] dealt last for 1 second longer. This effect stacks.
