Silver Palace Firtho Build: Serum and Team ATK

What is Firtho's Serum loop?

Special Serum is a small bar with a slow fill: a CBT2 cap of 10, regenerating at +1 per second. That makes ten seconds the cost of a full bar, and it makes every Second Heart decision a choice about how much of that bar to commit. Skills in Silver Palace have no cooldown, so the resource is the real cooldown — the general rule is set out in the combat guide.

There are two ways to spend it. A press spends 2.5 Serum for an immediate hit. A hold spends the full 10 and pays in health as well. Those are very different purchases, and the kit is built around the second one.

How does Second Heart work on a press?

Pressing the skill spends 2.5 Serum and deals 14.08% damage. The CBT2 sheet does not attach the team attack buff to the press, which means a press is a cheap damage button rather than the team buff. Four presses fit inside one full bar, so tapping is what you do when Serum is nearly full and you do not want to commit to the hold.

That also fits the character's design. Firtho is described as an output-oriented healer rather than a pure support, so spending spare Serum on damage is not wasted; it is the low-risk half of the kit, and it keeps the doctor contributing while the bar refills.

What happens during the long hold?

Holding Second Heart spends the entire 10 Serum and drains Firtho's health every 0.2 seconds for as long as the hold continues. Releasing deals 53.50% damage and applies the team heal and attack buff. The hold is the expensive, high-payout version, and the drain is the price that stops it being free.

There is an emergency exit. Blocking during the drain triggers a full charge and consumes all Serum, which ends the hold without waiting for your release timing. Treat the block as the abort button for when the health bar falls faster than expected — especially in a fight where the boss has just entered a new phase.

What does the Second Heart buff give the team?

On release the whole team gains +1.5% ATK, stacking up to eight times, with a 40-second duration. The same release heals the team, and allies other than Firtho receive an additional instant heal. The buff is the reason to hold at all: four presses cost the same bar and add slightly more listed damage than one release, but only the release changes what the rest of the party does.

The sheet does not state how many stacks a single release adds, only that eight are possible. Do not assume one hold equals eight stacks; watch the buff icon in game and count what one release actually grants before you plan a rotation around it.

How much damage does each input do?

Nothing else in the kit comes close to the ultimate. Visage of Death is listed at 169.60%, and Law of Exchange, the Tactical Assault, at 83.85%. Note who owns the Tactical Assault: it belongs to Firtho when Firtho is the character who enters on the swap, not to the character who leaves. The team building page covers that ownership rule.

Does Pain Management cover the whole party?

Pain Management reduces damage taken by 20% while the Second Heart buff is active, and the CBT2 sheet applies that to the team rather than to Firtho alone. That is what makes the health drain survivable: the hold costs health, but the buff it produces blunts incoming damage for everyone, including the healer paying the cost.

It also means the buff has defensive value even when nobody needs healing. A 40-second damage reduction window is worth holding for before a boss phase, not only after someone drops. The passive turns a healing decision into a mitigation decision, which is the more useful way to read it.

Where does Firtho fit in a team?

Firtho is a 4★ Radiatio Guardian with an output-healing kit. The Guardian identity and the healing put the character in the sustain slot; the Radiatio damage and the attack buff mean the slot is never passive. Team-wide attack buffs are one of the few ways a support slot can raise the whole party's output, and this one is paid for with a resource you can see on screen.

Outside combat Firtho is a doctor who works out of the Corner Clinic, treats patients in a sealed research room, and supplies medicine that offsets the side effects of the Detective's Mind Palace. The character has a congenital condition and wears a life-support rig, a neat narrative symmetry with a kit that spends its own health to heal others.

Common questions