User:Planterobloon/Finality

My Round 750 conception
My round 750 conception is the Keepers of Memory. This is a group, with each member becoming more powerful.

Balancer: This splits all but one Temple you have into a Sun God and its sacrifices, and destroys all but $500000 of your towers. This is to balance out your fight. This ability is passive, so you can't make another Temple or buy more than $500k in towers.

Origin
Origin is the first of the bosses you must face. It is sky-blue with "Bloons Tower Defense" written on it, and it purposely has BTD1-style graphics. Origin has 30,160 health, moves as fast as a green bloon, is immune to bombs and ice, and has several abilities:

The First Battle (passive): The rounds of BTD1 begin playing as soon as the battle begins, Apopalypse-style. If it reaches round 50 before Origin is popped, it will replay the round with more black and white bloons each time.

Off-Center (passive): Towers introduced after BTD1 have a 50% change to miss Origin with every attack, and an 80% chance to miss other bloons. Towers from BTD1 can still have upgrades introduced later (so a Juggernaut could still hit normally, for example), but a Temple with sacrifices from after BTD1 is affected. This is very bad if you use mostly slow-firing towers, but fast towers will still be fine.

One Difficulty (passive): When you buy anything, it is adjusted to its Medium price, regardless of your difficulty. Your lives cannot go above 150 until the battle ends, and they are dropped to 150 if they were higher.

Fight the Future: Origin leaves the screen for 20 seconds, taking towers from after BTD1 with him. Super Monkeys also leave. This means that your BTD1 towers have to fight the other bloons alone. After 20 seconds, Origin and other towers return to their previous places.

Time Skip: The rounds of BTD1 advance by 5 rounds instantly.

The original 4: Origin can switch between modes that represent each of the original towers. Each ability has the range of the tower Origin is copying, with their first long range upgrade enabled.

Dart Monkey: Origin can throw a dart that deals 10 damage to up to two towers in a straight line.

Tack Tower: Origin can shoot 8 projectiles, each dealing 5 damage.

Ice Tower: Origin freezes all towers within its range for 2 seconds. He can use this repeatedly.

Bomb Tower: Origin throws a bomb at a tower, dealing 8 damage to all towers within the blast range and unfreezing them.

Renewal
After you pop Origin, any once-per-round effects that your towers have take place, as if a round had passed, and your lives return to normal. Suddenly, the track changes to a random one on Expert difficulty or below. You must replace all your towers, and you have only 20 seconds to do so before Renewal spawns. Renewal has BTD2 graphics, has one each of blue, green and brown stripes, and is wearing a bronze, silver and gold medal. Renewal has 21,458 health, but it moves as fast as a yellow bloon and has lead immunities. Of course, it has abilities:

The start of a series (passive): Same as Origin's The First Battle, but sends BTD2 rounds instead. This time, it starts at round 10.

Monkey Glue (passive): Glue Gunners are destroyed. You get one Monkey Glue for every $30 your Glue Gunners would have sold for. Monkey Glue functions just like it did in the games it appeared in.

Life reduction (passive): To make this a little harder, your lives are set to what they were in the BTD2 version of your difficulty. You can still gain lives through abilities, however, and this can actually increase your lives if you were low.

Time Skip: The BTD2 rounds advance by 5 rounds instantly.

Newcomers: Renewal has modes just like Origin does. His are:

Laser Vision: Renewal shoots 18 pairs of laser shots in one second at either the closest or furthest tower from the end of the track. Each shot only does 1 damage, but there are 36 in total.

Sonic Boom: Renewal throws a boomerang in an arc. It deals 10 damage and can hurt up to 5 towers. Ice towers take 20 damage, and if the boomerang hits any towers, all bloons are unfrozen.

Road Items: Renewal throws road spikes and monkey glue around randomly (2-4 of each). These items have infinite range. If a tower is hit by road spikes, it takes 1 damage every time it fires until it has taken 10 damage. If it dies before the spikes run out, the spikes stay until Renewal is dead. If a tower is hit by monkey glue, it fires at half its normal rate until it has fired 20 times.

F.L.I.G.H.T.
The same thing happens once you pop Renewal as what happened when you popped Origin, but your lives don't return to normal. The track does, though, and your towers return to their former places. F.L.I.G.H.T. appears immediately after. F.L.I.G.H.T. is the first blimp to appear, and has 105,000 health. It also moves at the speed of a Green Bloon. F.L.I.G.H.T. has abilities.

Send in the Clones (passive): Same as before, but with BTD3 rounds. This time, it starts at round 20, and when round 50 is passed, it just randomly sends in rainbow and ceramic bloons, as well as M.O.A.B.s.

Blimp incarnate (passive): Towers that do extra damage to blimps have 10x their normal multiplier against F.L.I.G.H.T.

Pineapple bombs (passive): F.L.I.G.H.T. drops a pineapple bomb every 3-10 seconds that deals 8 damage to all towers in a pineapple bomb's range.

Time Skip: You know what this does.

Double Digit Towers: More modes.

Spike-O-Pult: F.L.I.G.H.T. throws three spiked balls that each deal 10 damage to all towers in a straight line.

Monkey Beacon: All bloons on-screen become 15% faster, but new bloons don't get this effect.

Plasma Vision: F.L.I.G.H.T. hits your strongest tower with a plasma stream that does 40 damage.

Super Monkey Storm: On death, F.L.I.G.H.T. deals 15 damage to all of your towers.

T.R.A.I.L.B.L.A.Z.E.R.
Your lives finally return to normal. Your tower buying limit increases to $999.999k, but you can still only have one temple. Trailblazer appears immediately. It moves at the speed of a Pink Bloon and has 288,400 health. Things are getting pretty hardcore now.

The Pioneer's Army (passive): Same as before, but with BTD4 rounds. This time, it starts at round 30, and makes random rounds after round 75 just like in BTD4.

Time Skip: Yes, AGAIN.

True Power: Even more modes.

Mortar Tower: Shoots a bomb at each of the three strongest towers that deal 20 damage each.

Glue Gunner: Shoots a glob of glue with twice the radius of a bomb that deals 1 damage per second to all hit towers for 10 seconds.

Monkey Ace: Shoots 16 darts in every direction that deal 5 damage each.

Monkey Buccaneer: Shoots 3 large darts in quick succession towards the three strongest towers that deal 10 damage to all towers in a straight line.

Monkey Apprentice: Switches the positions of two non-building towers.

Sun's Power: When T.R.A.I.L.B.L.A.Z.E.R. finally dies, it shoots sun beams in every direction (100 total). Each beam deals 2 damage.

F.I.N.A.L.I.T.Y.
There's no cost limit anymore, and you can have as many temples as you want. After 30 seconds, F.I.N.A.L.I.T.Y. appears. F.I.N.A.L.I.T.Y. moves as fast as a Pink Bloon, and has the immunities of a DDT and a Z.O.M.G.

The Final Warriors (passive): Bloons from BTD5, starting from round 40, appear.

Premium Debuffs (passive): If you have anything bought with NK Coins except for cash injections and life boosts, or any temporary boosts, they disappear.

Final Power: Guess what this is.

Sniper Monkey: Your strongest tower takes 50 damage and can't fire for 3 seconds.

Monkey Village: All bloons, new or not, gain 15% speed, and 50% more bloons appear for 10 seconds.

Dartling Gun: A Ray of Doom comes out from F.I.N.A.L.I.T.Y. that swings around randomly, dealing 1 damage every 1/4 second to every tower in it.

Spike Factory: Every tower is hit by road spikes (see Renewal).

The Cutscene
If you beat this and you've beaten E.N.T.I.T.Y., a cutscene plays. Bloonarius appears, and seems to be about to attack, when suddenly a bloon wrapped in a purple cloak appears.

Bloonarius: You may have beaten the others, but you will never... Wait, who are you?

???: Are you serious? This thing can't be real.

Bloonarius: How dare you mock my power! I am the god of *urk* (deflates)

???: Only we can destroy the monkeys. (turns to player) Don't you get it? We created your monkeys and the bloons, but we all know which ones we put more effort into. But then you destroyed all of our hard work! Even the E.N.T.I.T.Y.! You probably hacked to get this far, too. So consider this a bonus boss, if you will. One that's about to destroy you.

Wiki
It's not a blimp. It's far worse. Infinity.