Terabyte672 | Golden Sun - Crossbone Isle - Miniboss: Fifth Floor Guardians @Terabyte672 | Uploaded July 2009 | Updated October 2024, 1 hour ago.
Because you are unable to complete the previous floor until beating Colosso and receiving the Cloak Ball from Babi (You can actually visit Crossbone Isle before reaching Tolbi), the bosses at this point become noticeably tougher. However, they still aren't a HUGE threat as long as you're not just rushing into the battle with no forethought whatsoever.