All gamers are familiar with the different phases of boss battles. Once players whittle down their health enough, the second phase begins, and they return bigger and badder than before, the player having to amp up their play and come up with new strategies to win.
However, there are some bosses that don't have that immediate second or third phase. Instead, players defeat them and think they have won...until they return from the dead, usually in a different form, ar at least offering more of a challenge to players.
7 Ganondorf - The Legend Of Zelda
The Legend of Zelda by now spans multiple games in its franchise and a few spin-off titles as well, though few games are actual sequels to other entries in the series. Though there is a canonical order, the games mostly exist in alternate timelines with the main trio reincarnated in a different version of Hyrule, or even an entirely new location in certain titles such as Majora's Mask, with no memories of the previous games events.
As such, Ganondorf returns as the main boss in almost every game, threatening the safety of the kingdom and its Princess in each and every reincarnation, forcing Link to take up the sword and become the hero. No matter how many times Link kills him, Ganondorf returns once more in a different timeline, stretching on their rivalry until eternity.
6 Baldur - God Of War
2019 saw a pivot for the direction of the God of War series, pitting Kratos against the infamous Norse pantheon as he embarked on a quest with his son to spread the ashes of his wife from the top of a specific mountain. The journey was anything but free of peril and dangers, encountering many creatures and gods on his way there. One of which is the tragic son of Freya, Baldur.
Cursed to not be able to feel pain or anything good in life, Baldur turns bitter and hateful, becoming an antagonist in the series fueled by vengeance for the infliction his own mother placed on him. His 'curse' was born of her desire to save her son from death, causing Baldur to return from the dead after a skirmish with Kratos. While his curse comes with the unattended side effects that cause Baldur to turn cold towards his mother and life in general, it ensures his return from death
5 William Birkin - Resident Evil 2
The mad doctor from Resident Evil 2 fell from grace, injecting himself with one of the viruses he helped engineer, and turning into a recurring boss within the game, especially in Claire's playthrough. Whereas Leon will have to face off against the juggernaut Mr X at the games climax, Claire will have to fight William Birkin for one final time, eventually putting him down for good as the laboratory threatens to implode around them.
Claire and Leon will both face him shortly after their first exit from the police station, where they will play a game of cat and mouse around an enclosed maze of narrow hallways as Birkin chases them down with a metal pipe, though the true threat is Birkin himself, who can grab players that aren't careful enough. Once he falls to what players assume will be his doom, he returns later in the lab, and as the final boss for Claire.
4 Saren - Mass Effect
The original Mass Effect didn't have Shepard directly taking on reapers just yet, instead racing to save the galaxy against Saren's machinations, as he works alongside the geth to implement the reapers plans for universal domination. Though Shepard will encounter the ex-Spectre several times across the game, it isn't until the heart-pumping finale in the Citadel they will face off once and for all.
The first phase of the boss fight is an entirely optional one if Shepard's Paragon or Renegade rating his high enough. Instead of gunning him down, Saren will instead take his own life, and crash through the glass down to where the real final boss will happen. Though it's not uncommon for boss fights to be split into phases like this, Saren is more unique in that the second phase occurs posthumously, as his dead corpse becomes a puppet to the reapers.
3 Father Servo - NieR: Automata
NieR: Automata is a game filled with small secrets, optional bosses and endings the players can encounter, mostly by utter chance without the aid of an online guide. One of these optional fights can be encountered on one of the rooftops in the City Ruins, where a small robot that calls himself Father Servo awaits for someone to challenge him to combat. Players will enter a fight, defeating the robot, and leave.
However, should players return after some time, Father Servo will be back, only bigger than before, presenting more of a challenge. And that's not all. Players will fight against Father Servo and leave multiple times, seeing him return from his thorough trouncing multiple occasions until he is a ginormous goliath-type life form, which will be the final time players fight Father Servo, destroying him for good.
2 Jack Baker - Resident Evil 7
The terrifying patriarch of the Baker family proved to be one of the hardest to put down, with his penchant for returning from the dead on multiple occasions. Jack alone dies twice in the garage following the first proper boss encounter players have with him, once by Ethan's hand, and the next at Jack's own as he pulls Ethan's gun into his mouth and shoots himself to demonstrate the regenerative powers of the mold.
Players will encounter him a few more times throughout the game, including a boss involving a truly creative scissor-like chainsaw weapon Jack wields, until Ethan witnesses the true, mutated form of Jack as he becomes more mold than man, finally ending him for good.
1 Nemesis - Resident Evil 3
One of the ultimate stalk enemies from across all gaming, Nemesis is a terrifying juggernaut of raw strength and power that could give Mr X a run for his money. He is dead-set on eliminating all the surviving STARs members, relentlessly hunting Jill through the zombie-infested streets of Raccoon City. Jill will encounter Nemesis multiple times throughout the entirety of Resident Evil 3, serving as a boss on many occasions.
Jill will out down Nemesis with each encountering, believing herself to be free of him, only for him to return in a shocking twist, his body growing more mutated. Each encounter sees Nemesis's frame become marginally less humanoid and grow in size, forcing Jill to adopt new tactics to survive the fight. Nemesis proves tenacious, returning to life from hundreds of bullets, immolation of fire, and even being doused in acid.