I’m back with another ridiculously long and detailed suggestion. I hope it isn’t boring to read, and while, like the last suggestion I gave, I don’t expect all of it to be added, I hope it does give others ideas and I would still like feedback. (Also, I think I went a bit overboard with this).

Synopsis: The Master has had many incarnations and battles with the Doctor throughout the show. Like Davros, the Master always escapes at the end, and somehow even survives circumstances where he should have died. This suggestion is going to focus on that point, and try to summarize the Master’s different incarnations/stories. Fighting the Master also gives the player special items, and this is the only way to obtain them. Also included are several new dimensions, ores, and other features related to this idea.

?Round 1 (Rodger Delgado’s Master)

[Part 1]

To begin this boss fight, the player needs to take the TARDIS to the planet Uxarieus (as seen in Colony in Space). I am suggesting everything to begin there for several reasons: 

1: It establishes that the player has already obtained the TARDIS. The Master Boss fight is more of an end-game fight, and having the TARDIS establishes that the player has reached a more advanced level to fight the Master.

2: This one of the few non-earth planets that the Master appears on in his earliest form in the show (Roger Delgado’s incarnation). I am trying to summarize each incarnation of the Master in each leg of the boss fight, and therefore, several elements will be mixed together even if they took place in different stories/times.

Once on the planet Uxarieus, the player would have to search for the Master’s TARDIS (see above spoiler for details as to where), which is in the form of a spaceship (I’ve always had an idea that the sonic screwdriver can track down nearby TARDISes, perhaps that can be added and utilized to help the player). Once trying to open the doors, the Master will spawn, bearing a Rodger Delgado skin. A boss bar will appear in the top of the screen, and the Master will have a very high amount of health (about 200, same as the Ender Dragon).

The Master will attack the player, delivering a fair amount of attack damage (about 9 health/4.5 hearts). Further, if the player looks into the Master’s eyes, they will become “hypnotized”, or unable to attack until several seconds after they look away. (Back then, the Master would hypnotize people to get them to do what he wants, instead of nowadays, where he just tells them that they should listen to him because he’s crazy, and they do. Sorry, I’ll get back on track).

When half of the Master’s health is gone, he will flee back to his TARDIS and take off, leaving behind his dematerialization circuit, which at this point is a useless item, and a trophy for the player. He will also have dropped a piece of his TCE weapon.

[Part 2]

The Master will flee to Earth (Overworld, current), where the player must once again locate him. His TARDIS will again be somewhere within 5000 blocks from the map’s center, but this time will be in the form of a horse box. Once trying to open the TARDIS, the Master will again spawn, and will still have only half health. In addition to hypnosis, the Master will now spawn in Mobs around himself every so often while the player attacks him. The mobs can be Autons, Sea Devils (if/when added), Daleks, Axons (if/when added), all mobs this Master’s incarnation has worked with. After spawning in mobs, the Master will stop attacking the player for a minute or so, giving the player a chance to kill the mobs, and then refocus on the Master.

Once the Master is “killed”, the player will now be able to open his TARDIS, and once right-clicking the console with the Dematerialization Circuit, it will become operational and will belong to the player. It’s chameleon circuit options will feature all of the forms the Master’s TARDIS has had throughout the ages, and it will have hallways linking every version of console room his TARDISes have had in the show. The Master will also drop another piece of his TCE weapon.

?Round 2 (Peter Pratt’s Master)

Once the Player has unlocked Gallifrey (see here), they can again fight the Master, who has kept himself alive out of sheer hatred for the player, and now needs to restart his regeneration cycle through the Eye of Harmony, destroying Gallifrey in the process. The player must go the the Panopticon, in the Citadel, where they will find the Master in a very decayed state. This Master has less health, delivers a lower amount of attack damage, and can’t hypnotize the player, but the player has a limited amount of time to fight him (about two minutes at the most, the times can change based on the difficulty level). If the player fails to kill the Master in this time, they die on the spot as Gallifrey is “destroyed”. The battle will then reset, and the player must return to Gallifrey and start the fight all over again. Once the player defeats the Master, he will drop the Sash of Rassilon, which is the ultimate vanity clothing item that everyone wants (after some marketing). It also delivers a massive amount of protection when worn. (It is also an item required for becoming the Lord President, suggestion pending). And that’s that for the Master until he steals Tremas’s body on Traken.

?Round 3 (Anthony Ainley)

The planet Sarn is where the player can find the Master next. This is a barren planet that is mountainous, has lava in abundance, and has small villages with villager-like inhabitants. Deep in one of the mountains (closer to the map's centre than where he’s been found in the past) is a control room. There the player will encounter the “Master”. In this room is a control box, and a chamber containing blue flames, which will briefly give the player a regeneration effect if they stand inside them, but after 30 seconds the player will light on fire and stop regenerating. 

This version of the Master has a quarter of the health of the Delgado incarnation, but twice the attack damage. He also can’t hypnotize the player. When the player kills the Master, he will drop a chameleon block, for the player was fighting a hijacked Chameleon all along. He will also drop a third piece of his TCE Weapon, all these pieces can now be crafted to give the player a working TCE Weapon.

?Round 4 (New Series, part 1)

You’ve probably guessed that the Master isn’t gone yet. You can find him again by traveling all the way to the End of Time.

Once the player has arrived at the ET, they must find the Silo. Deep inside, lies Professor Yana, who has the same health and attack damage as the player. When the player gets inside Yana’s follow range, he will briefly get covered in a yellow particle effect, and start attacking the player. When he reaches 1 health (half a heart), he will begin regenerating, the player's TARDIS will be summoned to his location, and then dematerialize; Yana too will disappear. The player’s TARDIS key can no longer summon the TARDIS back. But he will also drop his fob watch, which can be used by the player in this suggestion.

However, the player has no time for a chameleon arch right now, because they have to get back to Earth. Fortunately, they have their vortex manipulator, right? If not, there will the the materials to build one there.

?Round 5 (New Series, part 2, John Simm)

The Master will take the player’s TARDIS to coordinates on the overworld, present time zone, that are relative to where the player’s TARDIS was in the ET Dimension. When the player returns to the overworld to defeat the Master again, they will find all mobs hostile to the player, including mobs like chickens and villagers (not sure if this is possible to code), but they can cloak themselves with their TARDIS key in order to avoid them. The player will now have to fight the most dangerous version of the Master yet.

This Master will have a John Simm skin, and as much health as the Delgado incarnation. This Master can hypnotize the player, summon waves of Toclofane, summon lightening at and around the player, as well as inflict them with slowness and weakness (comparable to how he made the 10th doctor old), and of course, deliver melee damage. The Master can only perform one type of attack at a time, and allow a cool down time between certain attacks before making another one (for instance, after summoning the toclofane, there will be a brief time allowing the player to kill them before he begins another attack).

When the player defeats this version of the Master, he will drop his Laser Screwdriver.

?Round 6 (New Series, part 3, Michelle Gomez)

[No, I'm done. Maybe I'll add to this after a future story]

TOO. LONG. TO. READ!!!!!!!!!

I love this. It might be too complicated for singleplayer, but it would be awesome in story mode!

To be honest, I never thought anyone would read all of this, it was just an idea I had been sitting on for a long time. 

But it's nice to know that someone liked it.

Nice. This wouldn't really be good for servers or possibly regular survival (I thinl it could work in normal DM survival, though).

Great suggestions! I think it would be kinda hard to make though.

Seems kind of long for a boss fight, but it kind of works and really like it.

Suggestion: Yana only demats the player's Tardis if Mobgriefing is set to "On."

Don't feel like reading it but knowing your suggestions, I love it haha

Thanks for the vote of confidence Malum, I mean Zeus.

And thanks for the positive feedback from everyone else, I honestly didn't think anyone would read or comment on this.

I didn't read the entire thing but...I approve :D

I read all of it, it is a great idea and I give it my support.

One thing though, :Suggestion: The Laser Screwdriver should only summon lightning that can burn mobs and other players, but not any block in the vicinity, thus preventing grief (as far as I know)

That's a great idea, I've put it into the screwdriver's spoiler.

This is an interesting topic to discuss, I'm liking this interpretation. It's unique and sticks to the show well!