It sounds as your tiel is in "nesting mode". This shows as he is ripping up newspaper to make nests and hissing/biting to protect their territory. My female cockatiel used to do this whilst she was in this mode, however she has grown out of it.

Yeah, this is common nesting behavior, this behavior will come and go as the seasons change. My female tiel gets very defensive of her cage at night mostly right before she is ready to lay eggs.

mine get a bit angry after about 7'o'clock if i don't take them in their cage (they have complete freedom of the house) i give them a sunflower seed each say goodnight(they reply) & then put a cover on the cage

in the morning if i am not up by 8 am they come to my bedroom & whistle/chatter at me till i get up

i have a galah not a cockatiel but i know for a fact if u feed bird corn they will be aggressive so if u are doing that stop another thing is whenever my bird gets angry it does everything else it can before unleashing his anger out on me so he might bite a toy or perch near him as if to say "i don't like that and i will bite you next" so that might be why he is bitting toys and stuff when he is angry just wait until breading season is over and he should be the same old bird again and just put a towel over his cage when he does this it might calm him down and if u can get a mate for him do so because he may not be getting enough attention if you go to school or work or uni or something

I'm not sure how old he is, but at night time he gets extremely angry. Some nights are worse than others, but it's every night. I know it's something to do with hormones because he masturbates on his perches and in the bottom corner of the cage while ripping up newspaper. If I come near the cage he hisses at me and will attempt to bite my hand if I put it near him. Some nights it's so bad that he screams at me and attacks all his toys (sometimes breaking them) and his broccoli.

The next morning he is fine. He is a good bird who trusts me and my other family members. He loves a good scratch on the head and loves to follow us around. He is out of the cage exploring most of the day.

We have looked up why he could be angry and everywhere says hormones. It also says it's breeding season for cockatiels in spring and summer. But it is winter here. It's been from -4 to 2 degrees Celsius at night and only gets up to 15 degrees in the day in July.

Also could this be because he is lonely and wants a mate?