Saintly Sister (Merciless) is an Advent Stage unlocked after clearing Dead by Encore. It appears on the 3rd, 4th, 17th, and 18th of every month. When clearing this stage, there is a chance to unlock Cossack Cat.
- Heavenly Herald Papuu spawns as the boss after 3.3 seconds100f.
- Infinite Sir Rels and infinite Wall Doges spawn after 10 seconds, delay 32.7~37.3 seconds1050~1120 and 46.7~49.3 seconds1400~1480f, respectively.
- 1 Sir Rel spawns after 13.3 seconds400f.
- 1 Dagshund spawns after 23.3 seconds700f.
- 2 Sir Rels spawn after 70 seconds2100f, delay 14.7~17.3 seconds440~520f.
- 1 Dagshund spawns after 117.7 seconds3500f.
- 2 Sir Rels spawn after 157.7 seconds4700f, delay 13.7~17.3 seconds440~520f.
- 1 Dagshund spawns after 203.3 seconds6100f.
It's practically impossible to prevent Papuu from ever damaging your base. However, Toxic doesn't affect the Cat Base, hence having more Cat Base health (from levels, Ototo Corps and Cat Combos) buys you more time to continue fighting.
Usable Uber Rares/Legend Rares include: Kachi-Kachi, Kasa Jizo, Wargod Yukimura, Snow Angel Twinstars, type Φ, Ushiwakamaru and Greater Demon Cat, to name a few, but most require a Rich Cat and a good strategy to be used effetively.
If you happen to have Hades, his Immune to Toxic ability and tremendous health allows him to tank many Papuu hits. If you can manage to inflict Curse on Papuu with units like Kasli the Bane, the entire stage become a lot easier.
It is also recommended that you try to fight 2 (or all three) Dagshunds before moving onto Heavenly Herald Papuu. If you trigger her "Strengthen" ability before killing the two or three of the Dagshunds, she can destroy your base much faster when dealing with the last Dagshund (though this probably doesn't matter if your cats are at a high enough level).
Strategy 1 (Uberless)
For this specific strategy, the use of Ubers or other units and Cat Combos in place of the recommended ones is heavily discouraged, except for Awakened Bahamut Cat and very few others. Use whatever Cannon you want (except Waterblast/Holy Blast), all have pros and cons.
Items: None are required, although a Rich Cat could help a little. A Treasure Radar is recommended after first clear.
Battle: Start by letting Papuu attack your Cat Base and get your Worker Cat to level 3, then take care of the Sir Rels with Ramen and Bullet Train Cat; it's crucial that the base never gets hit by them. Once you are done, spam Ramen for the rest of the fight, as for the other units, you want to ALWAYS wait for Papuu to attack, then summon them, but this doesn't mean that you should always summon them whenever you can:
- Bullet Train Cat is to snipe Sir Rel; if a Sir Rel is killed before you summon it, it can be good for Dagshund too.
- Fishman Cat is good for everything, but less important, so only summon him if you have money. Prioritize the others if there is too little.
- Seafarer Cat is here for his Survive ability. He can hold his ground against the White Enemies or the Sir Rels well, but should never be summoned against Papuu.
- Housewife Cat is here to snipe Sir Rels or Dagshunds thanks to her Long Distance ability.
- Ramen Cat is the main DPS source and only meatshield. Spam with priority.
The plan is to not bother keeping Papuu away from your base and just kill her. Ramen's DPS is really high, and since he can take up to 3 hits from Papuu, you can expect to have a small group attacking her after every wave of peons. The other units are here to make quick work of said peons, giving you more time to attack the boss. As for your base, you can expect to take about 150k damage, so you should be fine, as long as you have all Treasures for base health. Lastly, once Papuu gets stronger, do not panic and keep doing what you've been doing; if you added something like Awakened Bahamut for any reason, this is the time to spawn it.
In case of a loss, make sure you only summon cats (besides Ramen) just after Papuu's attacks. If you're already doing that, the problem lies in the levels of your cats, especially Ramen.
Note: In the featured attempt, Ramen was level 50+16 with a level 5 Attack Buff Talent, others around level 50; with this, the final health of the Cat Base was 84000/196000. If your Ramen is weaker, you still have plenty of health to give you extra time.
Strategy 2 (Ramen and Legs)
Lineup: (all Cats were at least lvl 40, Ramen should at least be lvl 50 including + levels)
Second line: Eraser Cat or Manic Eraser Cat, Ramen Cat (the author's was 50+24 with Defense Buff Talent level 5), Macho Leg Cat or Manic Macho Legs, Bullet Train Cat, and a rush unit (e.g., Awakened Bahamut Cat, Wind Dancer Valkyrie)
Items: Rich Cat (useful but can be done without it), Sniper the Cat, Treasure Radar (unless you're unsure if you can beat the stage)
Battle: The main goal is to prevent Sir Rels from hitting your base (if they do, you basically have no chance). When the battle starts, immediately send out Green Shell Cat and start spamming your Ramens and Erasers. When the first wave of peons starts, begin sending Macho Legs and Bullet Trains. Be careful as to not use Bullet Train for Papuu, it should only be used against the peons. Papuu will eventually start to hit your base, but keep spamming your meatshields and Macho Legs. If you feel like you're in a tight spot, send your rush unit out to buy some time and/or fire your Cat Cannon. Sniper the Cat should always be able to hit Papuu at some point and knock her back from your base. As long as no Sir Rels are able to hit your base, you will win. Ramen being the main source of DPS will carry through this entire stage.
Things to note:
- Being a tank, Green Shell Cat will not last long, so even if you send it, don't stop spamming cats.
- Keeping track of your rush unit's recharge is also important. If you have more than enough money, time it and send it at the peons or even Papuu. The faster Papuu dies, the better.
- Leave Sniper the Cat on the whole time. Sometimes people forget to turn it back on when they do turn it off.
- Timing Macho Legs well can easily kill the peons and leave Papuu open and give you more time to deal damage.
- If your whole first line is only Cat Combos, replace your rush unit with Green Shell.