Kryptonian and the bat son

Back story

Mari-el was from the planet krypton. She was sent to earth at the same time as the famous Kal-el or better known on earth as Clark Kent, the famous superman. However, when leaving, her pod got knocked off course, and when she finally arrived superman was in his 30's whilst she was still a child.

She landed near the league of assassins who were just celebrating the birth of the heir. They recognised the ship as a kryptonian one and where quick to take young Mari in. They decided that the new born would be betrothed to Damian when they both reached the age of 5.

Mari grew up in the league and she and Damian get along very well, they were inseparable. Of course, Mari got her special classes to help with her increase speed and strength. She was trained in hand to hand combat and with weapons. The league had come into contact with some kryptonite so when Mari did something against the league she was whipped with a kryptonite lined whip, much to Damians dismay.

The fact that little Mari was stronger then Damian never made him feel jealous, if anything it made him like her more.

"Come on dami!" A little 3 year old Mari shouted to the boy behind her.
"Not all of us have super speed!" The boy addressed as dami called from behind the alien girl. Mari sighed then waited for her slightly shorter friend. She then place on arm around his waist.
"Angel! What are you doing!" Damian hissed lowly at her.
"Helping you keep up." She replied innocently. She then proceeded to pick him up bridal style. "Let's go Demon!" She exclaimed brightly. The young boy groaned but still put his arms around her neck to prevent him from falling. Despite the displeasure he showed, he had a small up twitch of his lips showing that he didn't truly mind.

Talia had truly taken a liking to the young alien and had taken to often braiding her hair or telling her and her son stories of the great superman. She wouldn't admit to her father but if she could've, she would've kept both Mari and Damian away from the cruel life of an assassin.

There was a problem however. Mari refused to kill. She wouldn't do it no matter the punishment or begging from Damian to just do it so she wouldn't be hurt so much. Talia didn't want the youngling to be taken away so quickly preformed the betrothal ceremony before her father could discover Mari's persistent refusal.

The ceremony was very grand and every important assassin was present. Both children were 5 and they had there right palm cut; one with a normal dagger and one with a small piece of krypton. Some blood of each was then put in a goblet filled with the water of the lazuras pits. The children then proceeded to drink half of the drink each and it was complete. If either was intimate with a partner besides there betrothed, they would face great pain, although they weren't sure of the effect it would have on Mari.

When Mari was 7, Ra Al Ghul found out about her stubborn protest against killing. He had a long talk with talia and had eventually agreed that the girl was to valuable to get rid of. They told the little kryptonian that they were keeping her safe here and away from people who wanted to use her for her power and that she had to be trained to protect herself.

Mari was allowed more time outside due to the yellow star being the source that fuelled her power so most days mari and by extension Damian were allowed to train outside.

Then came the ambush against Ras. He was killed and beyond revival. Damian was taken to his father in Gotham. And Mari... well being that she was basically a living weapon she was sent to England with two league members. However, on the way the leaguers were killed and Mari was taken to France after being found by some bakers couple who thought she was a street kid due to the dirt covering her.

So in a matter of hours, both Damian and Maris lives where turned upside down and they only had one thing to hold onto. That one day they would meet again.