Rantiss · Server 8 ·
Short answer: yes. If Samuel is the lead hero of a joining march, Hydraulic Surge buffs the Guards of every march in the rally. It buffs Guards only. Bikers and Marksmen get nothing from it.
The skill text says "Guards under Samuel's command increase their Damage." Many players read "under his command" to mean "only the march Samuel is in," and so they keep Samuel out of joiner slots. My tests show that reading is wrong.
The skill
| Skill | Hydraulic Surge (Samuel's first Deploy Skill) |
| In-game text | "Guards under Samuel's command increase their Damage by X" |
| Value | +20% / +40% / +60% / +80% / +100% Damage (levels 1-5) |
| Fires | Once, at the start of the battle |
The test
I ran controlled rallies with two of my own accounts against the same target:
- The rally leader used Scarlett and Franklin, no Samuel. This stayed the same every run.
- The joiner either brought no heroes (run A) or Samuel as lead (run B).
- So the only difference between A and B was one copy of Hydraulic Surge (level 5, +100%), coming from the joiner.
- I ran the pair three times: once each with an all-Biker, an all-Guard, and an all-Marksman leader march.
All rallies were set up to lose on purpose. In a lost rally the enemy is not wiped out, so the number of enemy troops killed is a direct measure of how much damage the rally did.
Results
| Leader's troops | Enemy killed, no joiner hero | Enemy killed, joiner Samuel | Damage per round |
|---|---|---|---|
| 80,000 Bikers | 35,637 | 31,066 | no change (about 0.95x) |
| 80,000 Guards | 14,041 | 23,585 | about 1.7x |
| 80,000 Marksmen | 84,092 | 56,230 | no change (about 0.9x) |
- Guards: the joiner's Samuel nearly doubled the leader's Guard damage. The leader's Guards' normal attacks did about 2x the kills.
- Bikers: no gain. Run B was actually a bit lower, because that battle ran slightly shorter. Damage per round was the same.
- Marksmen: no gain. Run B killed fewer enemies because that battle ran about 25% shorter (with no guards to protect them, Marskmen die much faster, hence the shorter battle). Damage per round was the same, within normal variation.
Does it stack?
To test stacking, I repeated the Guard pair with Samuel added to the rally leader's march. Run A had only the leader's Samuel. Run B added a second Samuel as the joiner's lead. Both rallies lost, and both battles ran the same length.
| Leader's troops | Enemy killed, leader Samuel only | Enemy killed, leader + joiner Samuel | Normal-attack kills |
|---|---|---|---|
| 80,000 Guards | 74,471 | 86,437 | about 1.33x |
- Yes, it stacks. The second Samuel raised the Guards' normal-attack damage by about a third. If the second copy were wasted, there would be no change.
- Each copy adds less than the one before. The first copy gave about 1.7x. The second gave about 1.33x. This fits the bonuses adding together (+100% and +100% = +200%) rather than multiplying.
- Total kills rose less (+16%) than normal attacks, because Scarlett's and Franklin's skills happened to trigger less often in run B. Hydraulic Surge does not boost those skills.
What this means
- "Under his command" means the whole rally. A joiner's Samuel buffs the rally leader's Guards. The buff is not limited to the march Samuel rides in.
- It is Guards only. In a rally with few Guards, a joiner's Samuel adds little. In a Guard-heavy rally, it is one of the strongest joiner skills available.
- Samuel is a strong joiner lead for Guard-heavy rallies. You do not need him in the leader's march to get Hydraulic Surge.
- Samuel in the leader's march is still worth more than Samuel as a joiner, because the leader also gets Whirlwind Rescue (+25% Attack, whole squad) and Piercing Jet (+25% Penetration, whole squad). As a joiner, he brings only the Guard buff.
- Extra Samuels still help. A joiner's Samuel adds Guard damage even when the leader already has Samuel. Each extra copy adds a little less than the one before.
What I have not tested yet
- Every rally type. my tests were standard world-map rallies. Vault Trap and other event rallies very likely use the same battle rules, but I have not tested each one.
- One test pair per question. The gaps between results (1.7x vs 0.9-0.95x for troop type, 1.33x vs 1.0x for stacking) are larger than normal battle-to-battle variation, but more runs would tighten the numbers.
Why the battle report doesn't show this
The buff list in a battle report shows your pre-battle stats only (research, gear, hero stats, and similar). Skills that fire during the battle, like Hydraulic Surge, never appear there. The only way to see their effect is to compare the actual results of controlled rallies, as I did here.