Twenty-one escort craft — dragons, war-beetles, UFOs and two Transformers — that fly beside your fighter and pulse buffs on a timer. Internally the system is called "Guard"; economically it is the Sentinel Chip funnel: a refresh-gacha with a 0.2% jackpot, a 40-star ladder, and a four-slot passive recast.
Sentinels are the third companion collection, unlocked late — player level 58 (drones come at 45). A deployed Sentinel escorts your fighter and fires its Talent Skill on a fixed cycle: "After battle starts, release a skill every {n} seconds…". Every kit is that same sentence with a different payload — damage, healing, or a stacking buff.
The build guides in the client pair one Sentinel with a trio of drones per formation, and the Sentinel kits are transparently designed as the drone layer's support column: their skills and passives raise electric / burning / reflect enhancement — the exact three damage channels the drone elements deal — plus healing, crit and dodge.
A Sentinel's Talent Skill has 5 levels, gated by the Sentinel's own level: unlocked at Lv 1, upgraded at Lv 20 / 40 / 60 / 80.
Five SSR (including the Transformers collab units Onslaught and Ironhide), six SR, five R, three N and two G. The UI sorts them into five type families — Avian, Insecta, Special, Draconic, Wing Plane — which appear to be flavor/filter groupings; the mechanical identity lives in each unit's Talent Skill.
Every Talent Skill is the same chassis: fire every N seconds, deal (or heal) a % of ATK, apply a rider. The grade hierarchy is visible in the riders: SSR riders stack and last until battle ends (permanent snowball), while SR-and-below riders are timed buffs that expire. Healing kits are explicitly PvP-only ("Healing effect works only in PvP battles") — like drones, this layer's sharpest edge is the PvP metagame.
Owning specific Sentinels activates permanent account-wide set bonuses, each themed around the members' shared family — Fetters are the Sentinel equivalent of the drones' Combination sets. The premium set is Finale Overture: all four non-healer SSRs for +3% PvP damage — a collection tax squarely aimed at arena players.
Levels 1→150 cost Overclock Chips only, and the bill scales hard with grade: maxing a G costs 191,398 chips; an SSR costs 3,826,519 — exactly 20× — for 3× the stats (SSR caps at 18,656 HP / 4,664 ATK vs the G's 6,220 / 1,555).
A wrong investment can be undone: Reset refunds all materials and drops the Sentinel back to level 1, priced by grade (100 → 300 Diamonds, G → SSR). Star level survives the reset.
Reclaiming (selling) a Sentinel returns 80% of everything spent — and the client even dangles "a chance to obtain extra special items when reclaiming."
The full 150-level curve, every grade side by side — HP / ATK held at each level, and the Overclock Chip cost to advance from it:
Evolution consumes one same-name Sentinel per star, 40 stars total — so a maxed unit is 41 copies. Unlike drones there is no escalation: always one feeder per star. Each star adds a flat HP/ATK block, and every evolution also randomly upgrades a passive skill level or grants a new passive (up to the unit's slot cap) — evolution and the passive lottery are the same button.
Passive slots are the real grade gap: G/N/R hold 1–2 passives, SR holds 3, SSR holds 4. Each passive rolls from 18 families in three grades — Blue Purple Orange — at published odds of 73% / 18% / 9%, and levels 1–10 within each grade. The library is two mirrored halves: enhancements for your fleet (electric/burning/reflect/healing up, crit, dodge, Sentinel damage) and suppressions against the enemy's (the same list, downward) — pure PvP arms-race design.
Recast rerolls all unlocked passive slots (levels are retained) for 20 Recast Cores; results can be saved or discarded. Locking slots you want to keep costs Protection Cores, escalating steeply: 20 / 40 / 100 / 170 / 250 for 1–5 locks.
It's the drone recast loop re-skinned — reroll, preview, lock the keepers, pay more for each protected slot — pointed at a 4-slot SSR endgame: four Orange passives at level 10 each.
Everything runs on Sentinel Chips. Path one is the familiar refresh shop (same engine as drones): 10 chips per refresh, 4 free refreshes daily, buy what appears at list price (30 chips for a G up to 1,000 for an SSR). The published odds are the harshest in the game: SSR 0.2% — with a guaranteed R-or-better every 20 refreshes, and the auto-refresh robot ("Stop when SSR appears") happy to drain your stack.
Path two is the Sentinel Supply chest: 1 chip per draw. Only 20% of draws yield an actual unit; the other 80% pay out chest-shards that assemble into selectable chests. Every 100 supplies guarantees SR-or-SSR value, and the very first supply hands you a scripted SR-band unit to set the hook.
Duplicates also assemble from shards (20 → 100 by grade), and the hangar itself is monetized: 10 bag slots free, expandable to 50 at 500 Diamonds per slot.
The Sentinel Chip lane mirrors the drone store beat for beat: a free weekly trickle, then five escalating weekly packs. Chips also drip from Hypercoin and Wormhole-Badge exchange shops and daily-mission chests — but the arithmetic below is why the packs exist.
guard_main (roster, rates, passive roll odds), guard_level (750 rows), guard_star (205), guard_passive_skill(+_level) (54 + 540), guard_fetters, guard_unlock_skill, guard_type, guard_piece, game_base_param (guard_* economy constants), Supply chest via open_chest_config 109/112 → reward_new 223/1021–1023, packs from cfg_store.guard_ui_*, guard_skill_name/desc_*, evolution/recast/reclaim notices).