Guide
How the kit works
Enter with My Turn! to deal Electro DMG and switch modes. Tactical Tweaks also deals damage and switches modes. Huntress grants 30% Crit. DMG; Guts ignores 15% of the target's DEF.
With Gloves Are Comin' Off!, Normal Attack and Resonance Skill damage build Fervor. At 120 Fervor, hold Normal Attack for an enhanced heavy attack that pulls in nearby targets and deals Basic Attack DMG. In Huntress, you can also release Normal Attack during sustained fire at full Fervor to cast it.
Hot Hand regenerates at 10 points per second, and the enhanced heavy attack restores 40 points. At 120 Hot Hand, an Intro Skill or Resonance Skill activates both mode bonuses for 12s. Hot Hand cannot regenerate during that effect.
Mix-'n'-Match (Basic) lets Huntress hold Normal Attack for continuous fire. It costs STA and counts as Basic Attack DMG. During eligible attacks, press Dodge for a Tactical Dodge. Keep holding Normal Attack after the Huntress dodge to continue firing without consuming STA.
Use Resonance Liberation to fire the Mk. 31 HMG. Press or hold Normal Attack, or press Resonance Liberation, at intervals to increase its firepower up to twice. At full Overload, it finishes automatically; hold Resonance Liberation to finish early. Rebecca cannot move while firing, but gains 50% DMG Reduction and Immunity to Interrruption. Moonlit Clouds is the first set choice; its two-piece bonus gives 10% Energy Regen for using Liberation.
Switch out with Preem Choom. Its turret attacks for 14s, and the incoming Resonator gains 15% All DMG Amplification for 14s. Heavy Attack DMG Amplification builds over time, up to 35%. Switching away from that Resonator ends both buffs early.
Build and why
The game recommends Shadow of Shattered Dreams for Rebecca. Its effects are not included in the supplied data, so there is no set bonus to explain here. Moonlit Clouds is an alternative named by guides: its two-piece bonus gives 10% Energy Regen, which is useful for accessing her Liberation.
Skull Thrasher is the first weapon choice. It gives 12% ATK, 24% Basic Attack DMG Bonus after Intro Skill, and another 12% after inflicting Hack - Shifting. The latter trigger also gives the team 24% ATK for 30s. Rebecca's sustained Huntress fire, enhanced heavy attacks and machine-gun fire all count as Basic Attack DMG.
Phasic Homogenizer is another option: after a teammate uses Tune Break, it gives the wielder 20% All-Attribute DMG Bonus for 14s. Spectrum Blaster offers 36% Basic Attack DMG Bonus for 4s after Intro Skill or dealing Basic Attack DMG. For stats, ATK and Basic Attack DMG Bonus suit the attacks Rebecca uses often; Energy Regen is worth considering if you want more access to Liberation.
Leveling priority
As a suggested order, start with Gloves Are Comin' Off!, then Party 'til Dawn!, followed by Mix-'n'-Match. The Forte governs Fervor and the enhanced heavy attacks, while the Liberation covers the machine-gun attack. Level Tactical Tweaks and My Turn! afterward; both deal damage and switch modes.
For maximum ascension, collect 170,000 Shell Credit, 4 LF Mech Core, 12 MF Mech Core, 12 HF Mech Core, 4 FF Mech Core, 46 Nightmare Flashdrive and 60 Past Reveries.
To raise all skills to maximum, you need 2,030,000 Shell Credit, 25 LF Mech Core, 28 MF Mech Core, 40 HF Mech Core, 57 FF Mech Core, 26 We Who Question, 25 Incomplete Combustor, 28 Aftertune Combustor, 55 Remnant Combustor and 67 Reverb Combustor.
Resonance Chain nodes worth it
For a progression target, consider Maybe, Just Maybe... (Sequence 6). It increases Rebecca's Basic Attack DMG Bonus from every source by 40% and adds an Electro hit equal to 900% of her ATK during each enhanced heavy attack.
Oh, Hey Choom! (Sequence 2) is a useful earlier stopping point for team support. Intro Skill or Liberation grants the team 20% All-Attribute DMG Bonus for 30s, and a Resonator who inflicts Hack - Shifting gains 15% All DMG Amplification for 30s.
Don't Sweat Your Six! (Sequence 3) increases the Liberation and its finishing attack's DMG Multipliers by 60% and grants 120 Hot Hand on Intro Skill. If the team bonus is what you want, stopping at Sequence 2 and skipping later nodes is a reasonable choice.
Teams
Lucy is a natural recipient for Preem Choom. She immediately receives the maximum Heavy Attack DMG Amplification stacks, and she can enhance the turret: its DMG Multiplier increases by 250%, though its duration drops to 4s.
A teammate who can inflict Hack - Interfered through Tune Break lets Rebecca trigger her Hack response; each target can be damaged by it once every 8s. When a team member inflicts Hack - Shifting, that Resonator also gains 30 Tune Break Boost for 30s.
Common mistakes
Don't leave full Fervor unused while continuing ordinary attacks. Spend it on the enhanced heavy attack to pull enemies in and restore Hot Hand. Full Hot Hand also needs an Intro Skill or Resonance Skill to activate the combined mode bonuses.
Don't treat every heavy attack as Heavy Attack DMG. Huntress's sustained fire and both enhanced heavy attacks count as Basic Attack DMG, so a Basic Attack DMG Bonus fits those parts of the kit.
Don't switch away from the recipient of Rebecca's Outro too early if you want its buffs to last. During Liberation, remember that Rebecca cannot move: aim near the target you want, and hold Resonance Liberation if you need to end firing early.
