Underground is the sixth and last stage in Stairway to Darkness.
- 3 Shadow Boxer Ks spawn after 12 seconds360f, delay 8~20 seconds240f~600f.
- 15 Ginger Snaches spawn after 0 seconds0f, delay 0.33~6 seconds10f~180f.
- Infinite Ginger Snaches spawn after 0 seconds0f, delay 10~20 seconds300f~600f.
- Infinite Gabriels spawn after 33.33 seconds1,000f, delay 16.67~26.67 seconds500f~800f.
- When the base reaches 90% HP:
- 1 Bun Bun Black spawns as the boss after 0 seconds0f.
- Infinite Squire Rels spawn after 0 seconds0f, delay 2~6 seconds60f~180f.
- Infinite Gabriels spawn after 0.07 seconds2f, delay 8~20 seconds240f~600f.
- Infinite Heavenly Hippoes spawn after 0 seconds0f, delay 8~20 seconds240f~600f.
- 1 J.K Bun Bun spawns after 0 seconds0f.
- 1 Teacher Bun Bun spawns after 0 seconds0f.
- 25 Squire Rels spawn after 0 seconds0f, delay 0.07 seconds2f.
Note that if you sync the Bun Buns, the battle will become much easier. However, due to varied health and knockbacks, it is easy for them to get knocked back and will then proceed to plow your front line. Area cats such as Ururun Cat can knockback the Bun Buns back together, so that they are synced to make the battle easier.
There is a long distance between bases, so don't spam to many meatshields before hitting the base in order to avoid hitting the deploy limit.
Above all, DO NOT CONFIDE IN Necro-Dancer or any other single-target debuffs. They will likely hit the Hippoes instead and by the time any Bahamuts or ubers have taken care of the hippoes, the line would be pushed, and they would be dead.
Battle Items: Cat CPU.
Begin the battle, save money and advance the front line, Bahamut Cat and Ururun Wolf must not be spawned. Adjust the production to have max money and turn on the "Cat CPU" item when the Teacher Bun Buns appear (after damaging the Enemy Base).
Items: Cat CPU. (optional, only needed if you can't spam fast enough)
Battle: When the Ginger Snaches appear, lure them to your base, then start spamming meatshields and cameraman, with meatshields being top priority. A bit later, a Shadow Boxer K. will appear. Continue spamming meatshields and cameraman, and the shadow boxer should eventually die. This will give you a whole bunch of money, which you can use to spam sanzo, the meatshields, and cameraman, until you reach the base.
Once you trigger the boss wave, three Bun-Bun variants appear. Don't sweat it if they kill your sanzo stack or your cameraman stack though, as long you aren't incredibly unlucky, you should be able to push on. Keep spamming everything, as this phase gives you TONS of money. Once one of the bun buns dies, that is your signal that you have beaten this stage! The other two bun buns should be at low health and, therefore, easy to kill.
You can replace the crazed meatshields with other cheap 75¢ meatshields if you dont have them, although crazed wall is quite difficult to replace, as the bun buns will push extremely fast. Jiangshi works quite well in place of crazed wall if you have it, as it's survive ability gives you two for the price of one!