Cyclops is the only reason Erica isn't in the X-Men
In one reality, X-Men leader Cyclops died as a child, and Havok ended up being the leader of a team of mutants, with Elektra serving as his nanny.

The X-Men are no strangers to traveling through alternate timelines and realities, setting off a chain of events that led to the infamous assassin Elektra's alliance with mutants in a world where strong leader Cyclops died as a child.
The late 1990s episode "Mutant X" centers on Cyclops' brother Alex Summers aka Shockwave, who is propelled into another dimension by the explosion of a time-displacement machine. When he drowned in battle, his spirit entered the body of one of his variants. He was eventually rescued by his team of mutants (known as the Six), who then dispatched all the Sentinels they were fighting. However, Havok is appalled by this new reality. He assumes that the others are somehow conspiring against him, but they're just as wary of him because he's behaving quite differently now than the Alex Summers of that world.
Many of these changes are highlighted in Mutant X #1 by Howard Mackie, Tom Raney, and Andrew Pepoy. In this timeline, Scott Summers, also known as the mutant leader Cyclops, died in a plane crash as a young child. This event triggered the butterfly effect, leading to Completely different timeline of events. In this universe, Iceman was cursed by Loki, and Storm was bitten by Dracula and turned into a vampire. Additionally, Alex is married to Madeleine Pryor, also known as the Goblin Queen. They have a child named Scotty, named after Alex's dead brother. The most shocking twist, however, is that Electra is Scotty's nanny who must protect him from anti-mutant S.H.I.E.L.D. agents who try to kidnap him.
Cyclops's Death Changed Many Characters' Fates

The exact events that lead to Elektra becoming the babysitter for an X-Men-style mutant team have never been revealed. Most likely, the writers wanted a shocking nanny for the boy, and Elektra fit the bill. But it will be interesting to try to correct this drastic change in timeline. She still looks the same, and fights the same, so it's reasonable to believe she's likely received the same ninja training as the mainstream version of Hand. It's likely that Elektra owed Alex and his wife a debt at some point, or Elektra found that protecting children was a more fulfilling career than being a hired assassin.
what matters See how intense this universe would be without Cyclops. Essentially, Alex took his brother's place as one of the founding members of the X-Men. Then, when Professor Xavier fell ill, Magneto took over leadership of the group. The timeline gets messed up from there, and everything is very different. It's very similar to how The Flash saved his mother in DC Comics' Flashpoint and revolutionized the universe in the process. Cyclops must have been one of those people who had a profound effect on the timeline, and his death would change everything. His influence is so great, in fact, that if the world didn't have Cyclops, Erica would be doomed to ally with the X-Men.