Two slots

 'It seems I don't have a hope to surpass him.' Fey sighed, 'But at least, I had to follow his back!' She clenched as she didn't want her brother to leave her behind. She knew that she can't surpass her brother because she had witnessed her brother's talent in the past few days in her own eyes. If she could increase her strength by fifty percent in a year, her brother would literally double his comprehensive strength!

Fey set aside her current thoughts and ran hurriedly at her brother. "Are you okay?"

Fein raised his head. He looked at his sister with an exhausted face. "I'm fine. I just need to rest for a little." He smiled at her and quickly stuffed the sword in his scabbard.

'You've done a good job today buddy...' Fein expressed his satisfaction at his sword.

Suddenly, the sword received Fein's emotion through their mental connection. And buzzed for a few seconds before it stopped.