Do languages other than Turkish have intensified adjectives? How are these intensified adjectives constructed? I am especially interested in the case of Japanese.

To add to Achilleas Vortselas’ answer for Greek,

The prefix παν- “all” is another intensifier, which was also in use in Ancient Greek. So πάμμαυρος “all-black” (which is not ancient), παμμάταιος “all-vain” (which is).

Greek also has superlative adjectives (so μαυρότατος “blackest”).

And a colloquial (negative) intensifying prefix is in fact… καρα-, which is Turkish kara– in OP’s question. This is mostly used with nouns, e.g. καράβλαχος (not “black Wallachian”, but “damn hillbilly”), but it does extend to verbs (καρατσεκάρω “black + English check: “I’ll damn well check”), and occasionally adjectives:  Google has 673 instances of καραάσχετο, Internet Greek for “damned irrelevant” (i.e. “this is irrelevant to the thread, but…”)