Formatting harddrive

I've used Windows for the past 15 years or so. A friend of mine recently introduced me to Linux and I fell in love. I was using Windows 10 and before i installed Kali, I partitioned 200gb of my 1tb hd for Kali because I hadn't planned on fully commiting to Kali.

Ideally I would like Kali to be the ONLY operating system on my harddrive, all in one 900gb partition with 100gb designated to recovery/backup. What would be the best way to go about doing this? If at all possible, I'd like to avoid reformatting my whole harddrive and reinstalling Kali Linux. I'm not sure what format type to use either. When i go to reformat the 800ishGB partition that Windows 10 is installed on, I have the option of FAT, NTFS. Ext4, LUKS + Ext4, and custom.

If it matters, this computer is used primarily for downloading music, movies, gaming, and penetration testing.

I'd go with a dual boot option (Kali and Windows), since Kali is not designed/intended for music, movies, and gaming.

The Kali docs have good instructions for doing a dual-boot installation. With a 1 TB hard drive, I'd split it in half.

i agree with grid, or use some other Linux distribution like Ubuntu, Elementary OS...