Mass Effect Legendary Edition gathered all three games in the series, providing fans with the ultimate Mass Effect experience. The first and second entries feature some very challenging fights, particularly the fight against Saren and the suicide mission. However, it's undeniable that Mass Effect 3 is the most challenging entry in the series by a considerable margin.
Indeed, the game features incredibly difficult battles against a horde of enemies, including Reapers and Cerberus agents. Many players will struggle within these battles, but like Commander Shepard themselves, they will always find a way to come out on top.
The Battle Of Tuchanka
Priority: Tuchanka is one of the most exciting and important missions in Mass Effect 3. It features Shepard and his team traveling to Tuchanka to cure the genophage, resulting in the death of Mordin. The mission includes a multitude of enemies and features a final confrontation against a Reaper.
Most enemies are easy enough to handle, although the multiple ravagers pack quite a punch. The mission gets particularly in the final part when Shepard has to activate two hammers to call Kalros, a giant thresher maw capable of taking down the Reaper. The abundance of brutes is especially problematic, and players should focus on activating the hammers rather than trying to kill all the enemies.
The Banshees At The Ardat Yakshi Monastery
Banshees, asari mutated by Reaper technology, are among the toughest enemies in the game. Shepard first encounters them when doing the Ardat Yakshi monastery mission. Shepard reunites with Samara if she's still alive, and they fight several banshees throughout the monastery.
Reapers might be Mass Effect's main villains, but banshees are their most powerful weapon. The monastery mission features several attacks with multiple banshees, and things can get pretty intense if Shepard or their companions get too close to the monsters. The final portion of the mission, which involves defending a bomb against two banshees and several cannibals, can take players more than a few tries to complete.
The Geth Prime
Priority: Rannoch is one of the most difficult missions in Mass Effect 3. The geth dreadnought was challenging enough, pitting Shepard against a cascade of geth hostiles. However, things worsen when the Commander and their crew land on Rannoch to finish the mission.
Three brutal geth prime will ambush the party at one point, attacking mercilessly. These three are ruthless and powerful, and if players don't see the available Geth Spitfire, they'll have an incredibly hard time keeping up with the geth prime. Players might have difficulty even with the Spitfire because the weapon takes a while to charge, and geth prime are great at stunning with their variety of attacks.
The Reaper At Rannoch
And speaking of Priority: Rannoch, the mission's last part will put Shepard face-to-face with a Reaper. Using a laser, Shepard will have to attack the Reaper three times, working alongside the Normandy and the quarian fleet for maximum damage.
The Reaper will launch a deadly laser of its own, meaning Shepard will have to aim while evading the machine's attack. Things can get pretty intense after Shepard's first successful attack because the Reaper's laser will cover more ground and move faster. Players need to time their strikes and use the limited platform to the fullest if they wish to come out of the encounter in one piece.
Kai Leng, Rounds 1 & 2
The Illusive Man is the game's main human antagonist, but Kai Leng is probably the enemy fans hate the most. He is responsible for the deaths of Thane and potentially Miranda, and he has a smug attitude that makes him the leading contender for the most hated character in the series.
Shepard fights Kai Leng twice in the game, once during Priority: Thessia and one final time during the assault of the Cerberus base. The first encounter is particularly tricky because Kai Leng will always win, dealing a considerable blow to players' morale. The second fight is to the death, and Leng has a few tricks up his sleeve. His incredibly resistant shield can be a pain to wear down, but his final battle is somewhat disappointing, making him a great video game villain with an underwhelming boss battle.
Marauder Shields
Marauder Shields is the fan term for the final Marauder Shepard kills while making their way to the Reaper beam that takes them to the Citadel.
The Marauder is surprisingly tough to beat because Shepard is badly wounded by that point and has only a basic weapon to defend themselves. If Shepard is not fast enough, Marauder Shields will kill them with little trouble. Disappointed with the film's original ending, many fans jokingly stated Marauder wanted to save Shepard from the trilogy's underwhelming conclusion.
The Shepard Clone
Citadel is one of the best DLCs of the 2010s. Intentionally hilarious and full of Easter eggs and meta-commentary, Citadel has Shepard fight a clone of themselves created by Cerberus. The best part of the DLC comes after the mission ends, but the fight against the clone and their mercenaries is surprisingly challenging.
Particularly tough is the final battle aboard the Normandy. The clone has an obnoxious amount of shields and a large army of mercenaries. Things get more difficult when the ship's doors open and the ship loses stability, making the battle more hectic. Players should focus on taking down the clone and leave Brooks and the mercenaries to their companions. The battle will be hard, but the reward at the end is more than worth it.
Grissom Academy
Surprisingly, one of the most difficult battles in Mass Effect 3 comes early in the game. Grissom Academy: Emergency Evacuation involves Shepard traveling to the titular school to rescue the students. The Commander reunites with Jack while in the Academy, fighting their way through a swarm of Cerberus agents.
The battle at the atrium is particularly intense. Multiple Cerberus enemies will come from every side of the room, forcing players to watch their perimeter or risk getting killed by a stray bullet coming through their blind spot. The battle has two stages, so players need to stay near the shield generators and distribute their Medi-gels intelligently, or else they'll risk dying before the battle even begins.
The Final Stand
Priority: Earth is the final mission in the game, leading up to the most important decision players make in Mass Effect. However, before Shepard can reach the catalyst, they must make their way through No Man's Land, facing a seemingly endless cascade of enemies.
The hardest part comes when Shepard needs to defend the Thanix Missiles necessary to shoot the Reaper down. A parade of enemies will attack Shepard, including brutes, banshees, cannibals, marauders, and husks. Things turn for the worse when the Reaper begins firing its deadly laser, adding another dangerous element to the already savage battle. It gets overwhelming extremely fast, and most players will need several tries before they can win the battle.