its not a waste going to the castle. just bring alot of cooking items cause there is a cooking pot inside and your good. i like raiding the castle. lots of high quality weapons, bows and shields. im not even trying to beat the game but when im running low on supplies i raid the castle and always come back with some dope shyt because non-chest items always regenerate plus those dark hylian shiekah shields will last even if you messed up attempting to block a laser.Yea I beat all four Divine Beasts so they brought Gannon down to half health when I started fighting him. I only had to fight him in 3 forms: Normal, Metallic Gannon and Beast Gannon (final fight with the horse and bow of light). I also got all the captured memories.
I short cut through the castle to Gannon, cause I wasn't tryna waste weapons/food and time in the castle fighting the mini-bosses and guardians.
Next time I fight him I wanna go through the castle, but only if I have this ancient set ya'll were talking about, the guardian chainsaw (how tf do I get that?) and the Hylian shield.
note for castle raiders. don't bother renewing a rusty shield unless your ok with the regular knights shield.