It seems he is right I can sense it as well that I'm leaking with some magic my magic control is perfect what my grandpa said but we never tested my stealth capalities when I'm at fullpower.

James started moving at me faster but I'm still moving faster than him but he can predict my moves, which is ridiculous since I'm only leaking a small bit of mana.

I don't want to use any big spells since I don't want to waste my mana and I don't want him to die.

"You might be thinking, why can I sense you even tough leak barely enough mana to to reinforce a nail to be durable as an iron nail, well, it is because I have fought your parents who both were assassins that never leaked any mana both if they let me sense them even for a second it would be over since our core amounts were almost the same but you have more mana than both of them combined, which means that you can take me head on even while leaking some mana", James said while he was starting to activate some big spell probably to see if I could take it head on or would I dodge.

A big ball of lightning started flying torward me.

I don't know how much mana did he put inside the attack but I assume he put enough to damage me maybe a little. I take the ball of lightning head on and use my light and dark flower spell to absorb his attack.

The ball of lightning is hard to absorb it is like he has seen this move already.

"So you tried to use the same move you used on my son but it won't work since Jay told me all of the details that I needed to know. I wonder why you aren't going all out with your magic", James said while coming after me with murderous intent. I knew that I must learn to control the leak of my magical power if I wanted him to stop attacking me.

I must focus on controlling all the mana I currently have at my disposal. 

I'm picturing an endless ocean and a portal that is the supposed hole where my mana is going while it leaks. The ocean is is only dripping little drop of water through the portal but I must close this portal. I try to close it with my hands but it doesn't close so I'll just bottle the hole for a small time while I'm using a sea of unlimited magic or not unlimited but rather endless to humans.

I used a spell to absorb all of the light in the arena to make it dark as possible so he can't see me anymore. 

I'll move fast to end this fight. I'll go for his throat.

As the light started returning to the arena. I saw James being surprised when blade made out of darkness was next to his throat. 

"Good job, Allen I trust that you will make sure my son becomes a good young man but remember if it was outside fighting I'll use big spells" James said with a smile.