Undertale Storyline!

 MULTIVERSE TELEPORT 

To reach the level required to access the multiverse teleport, you'll need level 5+. To get that, you have to go ahead and farm some froggits, or farm flowey! He has 16 health points, and gives 30 EXP! Next, when you reach level 5, you can go into the Multiverse teleport, where you have to start off from the right side! You can first go to Snowdin, with level 5, and fight Papyrus! Note: The Papyrus boss itself requires only level 2.Papyrus has 100 health, and gives 200 EXP! Then, you can go into the Waterfall to fight Undyne with level 12!

 WATERFALL 

The waterfall has 3 portals. One back to spawn, one for Undyne, and one for Undyne the Undying. Undyne requires level 10, and has 250 HP and gives 850 EXP! Undyne the undying has 2000 HP, and gives a whopping 7000 EXP! The game works on the "first hit gets prize" system, so you can hit her and let a higher level kill her! Then lastly, on the same wall as undyne the undying, there is a hidden tem shop, where you can buy a toy knife for 100G, burnt pan for 600G, empty gun for 2000G, and a worn dagger for 4500G! You can buy health items, like the monster candy for 45G, Nice cream for 250G, Legendary Hero for 1000G, Face steak 3500G, Butterscotch Pie for 12500G, and Kindness soul for 20000G!

 HOTLANDS 

In the hotlands, if you go into the lab, you can fight Muffet if you go into the elevator, she has 420 health, and gives 1400 EXP! But, there is a secret boss, if you go into the lab, then go to the end, and into the DT extractor, you enter a long hallway. You reach the end, and you are greeted by Gaster! He has 100K HP, and gives 300K+ EXP!

 CORE 

There, you can fight either Asgore, Sans, Mettaton EX, or Mettaton Neo, each require respectively Level 14, 95, 15, and 60. When you go into Asgore's warp, you have 2 options. The barrier, or fight Asgore. Asgore has 1000 HP and gives 2350 EXP. Sans has 5000 HP, and gives 18000 EXP! Mettaton EX has 450 HP, and gives 1599 EXP! Lastly, Mettaton NEO has 2000 HP and gives 7000 EXP!

 THE BARRIER 

The barrier is a warp that needs level 50! I'm sure by now you have level 50, at least.There you can fight asriel dreemur at level 35, Chara at 90, Photoshop Flowey at 100, and Determined Frisk at 172! But wait, that's not it! If you go behind Frisk, you go to an extended part of the barrier! There, you can fight Asriel Dreemur God Of Hyperdeath at level 500, and Six Souls Asgore at level 1700!

Now that we finished those, time for the spicy stuff.

There is also Aus of Sanses