Please note that I'm not actually following what the game said/did at the end of Arthur and Mary's relationship. I always loved their relationship. This is a fanfiction, after all. Judge if you want.
Arthur walked through the forest, looking at the beautiful flower buds that were floating down from the trees. He stopped at a small stream, looking at his deer reflection for a minute before slowly drinking the crystal clear water. He swallowed, the cold, refreshing liquid going down his throat, then he continued drinking. The pond was located by a low hanging tree branch and the big valley in front of it.
Hello, Arthur.
The buck coughed and looked up, still having a mouthful of water in his cheeks. A doe stood before him.
Don't you remember me?
The doe stepped into the water, closer to Arthur and he backed up. The Doe's pelt glisined in the sunlight and Arthur gulped hard, swallowing the water in the process.
It's me, Mary.
Arthur continued backing up as she approached slowly, and his hoof slipped on a wet rock, causing him to fall in the water. Mary giggled and continued walking to him. The buck quickly got up and started to back away in a hurry, but accidentally got his antlers caught in a low hanging branch. Mary continued twords him. Arthur gasped and tried to pull his antlers free from the branches.
Oh no... No... NO...!
The doe licked his cheek and his eyes widen with confusion and happiness. Arthur shook his head, his antlers getting free from the branches, and he swooned.
The two deer played in the flowery field and John, Jack and Abigail arrived at the hill top to see why their family member was taking so long. Jack looked at his mother. "Ma, what's Arthur doing? Why is he with that doe?" he asked. Abigail smiled at the two animals then looked at Jack. "Seems Arthur found a new friend," she said. Mary disappeared into a bush and Arthur stuck his head through, trying to find her. A stag glared at him and he forced Arthur back.
John gasped a little as Arthur was forced to back up. "This isn't good," he said. Jack turned to his father. "Why? What's happening?" He could see Arthur's herd standing a little ways back. Every deer was looking at the two males. "Arthur's being challenged," Abigail answered. Mary walked up to her friend.
Arthur.
She looked at the other buck and narrowed her eyes. She and Arthur started twords each other but the stag forced Arthur back again. The stag forced the Doe to come with him. Arthur watched.
Arthur!
The buck stood there. Mary cried his name again. Arthur pawed his hoof on the ground and snorted angerly. On the hill, John got a little excited. "Oh boy, here we go. A stag battle! The other deer is challenging Arthur for the role of leader and the doe."
Arthur and the stag clashed, locking antlers and threw each other to the ground. The stag had the upper hoof. He rammed the golden colored buck into the ground and jabbed his ribs with his sharp hooves.
"We gotta help Uncle Arthur!" Jack yelled as he made a move to get up, but John held his arm. "This is his fight, son. Not ours."
The buck let out a call in pain and Mary gasped. Eventually, Arthur was able to lock his antlers with the stag's and throw him into a tree. The stag limped away, defeated. Arthur had won.