2-1 Sun-Dappled Bank Go to the Lake and get a decent mon anything really works lol if you can try to get a Psyduck or Lombre then gg return to Town
Psyduck ✅✅✅✅✅ Lombre ✅✅✅✅✅ Bibarel ✅✅✅✅✅ Palpitoad ✅✅✅✅✅ Anything else with Water Gun ✅✅✅✅☑
The first fort is a joke, you just 2 hit if not OHKO everything
2-2 Misty Edgewater Drilbur Hole, then go to the Hauntyard. If the mon you used to beat Krookodile with doesn't have a water type attack, scoop up a mon with a ghost attack and beat Lampent Go back in and get at least 3 decent Ghost mons
Lick Ghastly ✅✅✅✅✅ Lick/Astonish anything ✅✅✅✅☑ Night Shade anything ✅✅✅☑☑ Ember Litwick ✅✅✅☑☑ Shadow Sneak 💩
Defeat the BR and enter the fort, you don't need to go back and heal, there are glowdrops in the fort. The entire fort is filled with Psychic types, so you can just plow through it with your Ghost types. If you are using Ghastly, be careful in the 3rd room of Kirlias being sneaky with Confusion.
2-3 Soothing Shore Drilbur Hole and go to the Tower, get Scraggys, beat the Scrafty, go back for more Scraggies and take on the Fort
Scrafty ✅✅✅✅✅ Scraggy ✅✅✅✅✅ Twinneedle Ariados ✅✅☑☑☑ Everything Else 💩
Just skip the BR lol
2-4 Shimmering Lake Go to the Treetops and try to get Volbeat/Illumise with a good bug move like Signal Beam or a Roselia with Poison Sting. Also you should get a hard hitting mon with a grass move while you're here. Then fight Liligant who Petal Dances and heals with Synthysis. Alternitively you can go to the cave and get Dig Drilbur which is a REQUIREMENT for beating the boss (Excadrill) reasonably quickly. Also if Excadrill breaths on you it will OHKO. After beating one boss, go to the Lake and beat Seismetoad. It helps if you have a Roselia/Wormadam/Liligant/Cherrim with Magical Leaf/Giga Drain/Grass Knot
After that go back to the Lake over and over until you catch like 10 Basculins
Basculin ✅✅✅✅✅ Seaking ✅✅✅✅✅ Bubblebeam Krabby ✅✅✅✅☑ Bubblebeam Palpitoad ✅✅✅☑☑ Metal Claw Krabby ✅✅☑☑☑
Do the BR then the CB (Charge Battle)
Great Glowing Fountain is like a minute and a half cutscene. If you made a coffee earlier you can go grab it and it's probably cooled off by now. Switch to Victini or Pikachu and go fight Cobalion Solo, let yourself get slaughtered by Sacred Sword