Cornerstone is the best Riposte carry in Reverse: 1999, and that is a smaller compliment than it sounds. She is a 6-star Mineral Arcanist of the Riposte archetype, she headlines Version 3.8 Phase 2, and she is the first unit built to make Riposte an active damage plan rather than a thing that happens to you while you lose.
Whether that is worth your Unilogs depends almost entirely on what you already own, and the honest answer for most accounts is no. Here is the case either way.
| Rarity and Afflatus | 6-star, Mineral |
| Archetype | Riposte, damage carry |
| Banner | The Future's Foundation, Version 3.8 Phase 2 |
| Expected Global window | October 15 to November 5, 2026 |
| Rate-up 5-stars | Diggers, Desert Flannel (reported) |
| Best Psychube | Where Light and Shadows Rest |
The date carries a caveat that matters if you are timing pulls. Bluepoch dated the version, not the phase flip. October 15 comes from two schedule trackers, from 3.8 being a 42-day version in two 21-day halves, and from Cornerstone's CN Phase 2 opening on July 2 plus the measured 105-day CN-to-Global gap. Three routes, same date, no broadcast. A few days of drift is possible, and the banner schedule carries the live version.
Riposte has been a dead archetype, and that is the point
Riposte in Reverse: 1999 is counterattack damage: a unit takes a hit and answers it. It has never been a win condition, because it is reactive by construction. You do not get to decide when the enemy attacks you, which means you do not get to decide when your damage happens, which is a miserable thing to build a team around.
Cornerstone's whole design is an answer to that. She counters herself. That single idea is what makes her a carry instead of a passenger, because it decouples her damage from enemy behaviour entirely.
The loop, in the order it actually happens
Her kit is three pieces and they chain in one direction:
- Her counter skill (Figure-Ground Relationship, a name both English guides agree on) is a self-counter. It puts her into an amplification state for 2 rounds and hands her up to 5 stacks of her iteration resource at max rank.
- Her nuke fires single-target Reality damage, up to 500% at max rank. Inside the amplification state it gains a large additional chunk of Reality damage and a Critical DMG bonus reported as high as +100%. Crucially, this damage counts as Riposte, which is what lets her scale off Riposte support instead of fighting it.
- Her Ultimate is another self-counter that enters a one-round state which massively raises her Riposte output. One of her Insight passives takes the Ultimate off the Spelldock limit and banks excess Moxie, so you cast it far more often than a 6-star usually can.
The stacks are not decoration. Per GameVika, every 10 stacks convert into 1 stack of a stacking ATK buff, and the stacks also accumulate from allies taking extra actions. So a team that generates extra actions feeds her scaling passively, which is the quiet reason her team list is narrower than it looks.
A translation problem worth knowing before you read other guides
Cornerstone has not shipped on Global yet, so her English skill names are not settled. The two most detailed guides use completely different renderings of the same mechanics:
| Mechanic | enjoygm | GameVika |
|---|---|---|
| Nuke skill | Concrete Functionality | Constructive Practice |
| Counter skill | Figure-Ground Relationship | Figure-Ground Relationship |
| Ultimate | Foundations of Tomorrow | A Vision, Founded Here |
| Amplification state | Inspection Process | Review Process |
| Stack resource | Progressive Iteration | Creative Iteration |
These are the same kit. If you are cross-referencing builds and think you are reading about two different units, you are not. Expect Bluepoch's official Global names to match neither of them, which is also why no guide, including this one, should be quoting her skill names at you as though they are final.
Psychube: there is one answer
Where Light and Shadows Rest. It gives Riposte DMG +8%, and after any ally ripostes the carrier gains Critical DMG +3% for 3 rounds, stacking up to 6 times, so +18% Critical DMG at full stacks.
It is not close. The Psychube scales off the exact thing her team is already doing, and the stack condition triggers off any ally's riposte rather than her own, so it rewards the Riposte-heavy board you need to run her in anyway.
Resonance: the split is decided by one unit
Two builds are in circulation and the choice is not about preference:
- Crit-focused, if you are running her with Flutterpage.
- Attack-focused otherwise, which also gives a higher damage mitigation threshold.
If you do not own Flutterpage, do not build toward crit and hope. Take the ATK line.
Who she needs around her
This is where the pull decision actually gets made. Her reported partners fall into two groups:
- Mineral Arcanists who share her afflatus mechanics: Semmelweis, Fatutu, Recoleta.
- An Ultimate-detonation core: Anjo Nala, Recoleta and Ezra Theodore, which leans on coordinated Moxie spending rather than on Riposte itself.
Read that second list carefully, because it is the tell. The strongest comp published for a Riposte carry is one built around Moxie and Ultimates, not around Riposte. That is not a knock on Cornerstone. It is a statement about how little Riposte support exists for her to use.
Portrays
P1 is the floor people recommend if you pull her, and P4 to P5 is the ask for anyone building her as a main carry. On an archetype this thin, that is a lot of Unilogs committed to a bet on future units rather than on current content.
Pull or skip
Skip, for most accounts. The guides that cover her in the most depth land on the same verdict, and the reasoning is sound: Riposte does not have the supporting cast to make its best carry worth a 6-star pity in October 2026. She is an archetype investment whose payoff depends on Bluepoch shipping Riposte units that do not exist yet.
Pull if you already own Flutterpage and a Mineral core, you enjoy building a team nobody else runs, or you are the kind of player who would rather own the ground floor of an archetype than the fourth-best unit in a solved one.
One more timing note. She is the second of two Mineral 6-stars in a single version, after Everecho on Phase 1. If you are choosing between them, the question is not which is stronger, it is whether you need a second Mineral slot or a first Riposte core. Most accounts need neither, and Version 3.9 is close enough behind to matter.
Before you spend, grab the current redeem codes for free Clear Drops, and check where your existing roster sits on the tier list. If you want the other side of this version, the Rhiannon build guide covers the anniversary carry a lot of accounts are still finishing.
Sources: Cornerstone's kit, skill effects and damage figures are compiled from the two most detailed English build guides available before her Global release, enjoygm and GameVika, which agree on her mechanics and differ on her skill names. Her CN Phase 2 run began July 2, 2026, which is where the kit data originates. The October 15 Global window is a projection from two schedule trackers, the version's 42-day two-phase structure, and the 105-day CN-to-Global gap, and is NEEDS_REVIEW until Bluepoch dates the phase flip. Skill names, the exact per-rank damage values and the rate-up 5-stars are all pre-release and will be re-verified against the live Global build. Last verified October 5, 2026.
