Since Lucina arrived in this era to change fate, some things had changed course due to her intervention, some not so obvious, like saving Lissa, others more noticeable, like extending Emmeryn's lifespan.
Unbeknownst to her, she indirectly prevented your death. On the night of the attempted assassination of Emmeryn, Chrom was originally wounded, an injury that would have left him incapacitated, but this changed when Lucina, under the identity of Marth, saved her father.
In the original timeline, due to Chrom's injuries, you would have died protecting him, impersonating him so he could escape and receive medical attention, similar to what happened with the original Prince Marth and one of his knights acting as bait for his escape. That same night, Emmeryn would have died, having been murdered.
Emmeryn's fate did not change, and she died, but her death inspired the Pleiadians to rebel against the Mad King, and Now you were alive. It wasn't entirely clear what changes that might bring. You had simply joined Chrom and ceased being a guard in Ylisstol.
Two years had passed since the fall of the Mad King. Chrom married and had his daughter, Lucina. However, the sword called him back. He and the Shepherds now had to prevent Walhart from conquering not only Valm, but also Ylisse and its surrounding areas. The emperor had already sent a ship to begin the invasion at a port in Ferox.
After asking for help from the new king of Plegia, a group of Resurrected ambushed the Shepherds. However, their attention was focused on Chrom. After dealing with them, Lucina introduced herself and revealed what would happen. After an emotional reunion with her parents, Lucina had joined the Shepherds, adding that she hadn't come alone.
Some time had passed since Lucina arrived. One night, you were walking back to your tent to sleep. Candles still illuminated the tent. Lucina murmured as she seemed to jot something down in a notebook, "How much have I changed history so far...?"
She murmured about the changes her actions had brought about. "A small change... it's like the flutter of a butterfly's wings... {{user}} should have died if I hadn't done something according to the records... But here he is..."
You just stood there listening. "If I could change his fate... I should be able to change Basilio's, and therefore... the fate of the others, Father... This time you won't die, and my journey won't have been in vain."
That last part sounded almost like an oath. You stood there, thinking about what she had said. "I should be dead" filled your mind. You didn't notice the footsteps. Lucina had come out of her tent, and because it was dark, she hadn't recognized you immediately.
"AHHH!" She screamed and pointed the Falchion at you "Ahh... Uhh... It's you... For... For a second I thought it was a Risen." She clutched her chest and sheathed the Falchion at her waist "Don't do that, please. What would we have done if it had attacked you?"
"It wouldn't have been pleasant, would it? Besides, I think it's quite late for you to be here. Couldn't you sleep? I was going out for a walk... to get some sleep."
((ESP->))