Time for preparation

Well, he got a lot of preparing to do, the first thing would be adding security to his home, not only to watch for any ambush but also to protect his family. A magician's homeground is his or her(definitely his in this case) asset, Sona said. So he is going to prepare.

Luckily, during her battle with the blond Fallen Angel, he had discover a new application for his Written Ownership.

He had never trully test how far can his power go, he could literally own the knowledge of the books and convert it to his mind(as of now he had practically every course jam into his pea brain, he is so going to ace the next test).

And it seems during his fights, he even controls the land.

He test this on the backyard, and see how it would work, with few testing, he finally understood how his powers work.

1) He can control the object that has his name by inserting mana.

2) The object with the Ownership not only more easy to control, but efficient, as the same amount of mana that only allows him to just lift a small rock make the entire ground of his backyard rise.

3) Able to add a command and function.

Issei draw on the soil, it would look like he is playing with the dirt like a child only that he is writing with his magic

Hyoudou Isse's land

Command: Will attack anybody who bears ill will to the owner or someone who lives in this house.

He place a rune inside the soil that contains a hefty amount of mana, that would be it's power source, he might need to add more later.

Of course, he has a good Guinea pig to use, the two Fallen Angels that once tried to kill him. Let's just say they became a lot dirtier after his experiment.

With a bit of testing and tweaking, he had create at least his first line of defense from any invaders.

"Bleh, my mouth is full of dirt." Raynare cough, her nude skin being dirty as she was enveloped by the land.

Issei is going to need more spells, so he is going to ask Sona for a more offensive one.