ArknightsChallenge Gacha

Arknights Challenge Gacha is an unofficial fan tool for challenge runs in the mobile tower-defense game Arknights. It picks 12 random operators from every operator released on the global (EN/JP/KR) servers, and you clear stages with exactly that squad. No sign-up, no login, works in your phone's browser. The fun happens in the game; this site only creates the restriction.

Basic flow

1. Pick a difficulty. Default is Easy. Difficulty only changes the rarity odds of the operators you roll, not the stage. "All ★6" and "Easy" suit well-developed accounts; "Normal" and "Mon3tr" mix in ★3 and below.
2. Press ROLL. 12 cards appear face down. Even face down, the card color shows the rarity and the icon shows the class.
3. Flip the cards. Tap to flip one at a time, or "Flip all". Tap a flipped card again to see the full illustration, name, rarity and class.
4. Reroll operators you don't own. Press "Reroll selected", tap the cards, then "Reroll". Only those cards are rerolled at the same rarity, without duplicates. No limit. Under-leveled operators are not a reason to reroll: raise them instead.
5. Share. "Share" builds a result image on the spot and sends it, with hashtags, to X or other apps. If the share button is missing on your device, save the image and post it.
6. Build the squad in game and go. Support units from friends are off by default.

Class guarantee "Off" is fully random: no medic, four guards, anything can happen. "On" fills the top two rows with one operator of each class in order (Vanguard, Guard, Defender, Sniper, Caster, Medic, Supporter, Specialist) and rolls the last four slots at random. With "On", operators from smaller classes appear a little more often (see FAQ).

SSS Press the small "SSS" pill above the difficulty to roll a 20-operator starting squad for Stationary Security Service. With class guarantee on, each class gets two operators (top four rows) and the last four slots are random.

Squad size and classes Press "Size / Class" above the difficulty to roll anywhere from 1 to 12 operators. Pick classes to roll only from those (none picked means all classes). For example, size 1 plus Medic rolls a single medic. When classes are restricted, the share image says so.

Lock operators Press "Lock operators" at the top right of the squad, then tap an empty slot to search for an operator by name. Alter operators show up when you search for the original name (Texas, Ch'en and so on). If you can't remember the full name, the "Alter" button next to the search box lists alter operators only, so you can pick from there. After a roll, press "Lock operators" and tap a card to lock that operator. Locked operators stay face up and unchanged through "Roll again" and rerolls. Locked cards carry a lock mark in the top-left corner, both on screen and in the share image. To unlock, press "Lock operators" and tap the locked card.

Link ID Link a share URL from Arknights Shared Viewer to exclude operators you don't own. Details are behind the "i" next to the "Link ID" pill. Everything works without linking.

Difficulty sets the rarity odds. For each of the 12 slots the rarity is rolled first, then one operator is picked uniformly from that rarity among those not yet rolled. No duplicates within a squad. With class guarantee on, the first 8 slots are rolled per class before the remaining 4.

Card frames: ★6 glossy gold, ★5 yellow, ★4 blue, ★3 and below white.

• No rerolls: leave unowned slots empty.
• Promotion / level caps: E1 only, level 50, and so on.
• No support units.
• Skill lock: everyone on skill 1, or pick skills at random.
• Farming runs: clear material stages or Annihilation with the rolled squad only.
• Same squad with friends: share the image and compare results on the same stage.

Do CN-only operators appear?

No. The roster follows the global (JP) server data, so only operators released on global servers are included. Names are taken from the EN server data.

When are new operators added?

The roster updates automatically every week, usually within a week of release.

Are collab and event-only operators included?

Yes. If one you can't obtain shows up, use "Reroll selected". Reserve operators and other non-playable characters are excluded.

Are operators of the same rarity equally likely?

With class guarantee off, yes: after the rarity roll, one operator is picked uniformly using the browser's cryptographic random generator. With class guarantee on, operators are equally likely within the same class and rarity, but smaller classes (for example 8 ★6 medics vs 29 ★6 guards) get a higher per-operator rate. That is inherent to guaranteeing one per class.

Does it work for Stationary Security Service?

Yes. Press "SSS" above the difficulty, then roll to get a 20-operator starting squad. With class guarantee on, each of the 8 classes gets two operators (top four rows) and the last four slots are random. Mid-run recruitment is already randomized by the game, so just play it as is. The share image and post text are labeled "SSS".

How much data does it use?

One roll loads 12 face icons, about 600 KB in total (less on later rolls, since your browser keeps the icons it has already loaded). The full illustrations shown when you tap a card are large, 1–4 MB each, so go easy on them if you are on mobile data.

Can I roll only from operators I own?

Yes. Press "Link ID" and paste a share URL from Arknights Shared Viewer (by OperatorManageToolマン, @an_mngtool). Unowned operators are then excluded. The link is stored only in your browser. After linking, "Exclude unraised (E0 Lv1)" also leaves out operators you have not raised at all. No other level or promotion filter is available.

I keep getting operators I haven't raised. Can you add a blacklist?

There are no plans for one. If an unraised operator shows up, please raise them. If you have linked an ID, there is a setting that leaves out operators still at Elite 0, level 1.

Images don't show, only names.

Images are loaded from external sites and may fail on some connections. The rarity color and class icon still show, and the name is displayed in place of the image.

Is anything saved?

No. Results disappear when you close the page; save the image if you want to keep them.

Is it free? Do I need an account?

Free, no sign-up, no login, and no connection to your game account.