JackPlatinum is an incredibly dense pile of platinum slag able to formulate into a solid. He was first introduced in the third FTS, but those were bad posts, and bad times, so he was deleted. Later, in FTS4, he was reintroduced when mega man, Samus, and luigis ghost were exploring the slag dimension.
JackPlatinum is incredibly dense, has superstrength, and knows karate. He also can clone himself and is nearly indistructible, and can of course turn back into a pile of slag at will, and as a result can "eat" anything.
The Illuminati is known to hate him, as in the removed posts, they tried to kidnap him and sell him for billions of dollars. Other than that, his "siblings" copper, bronze, silver, and gold hate him because he abandoned them in the slag realm.
JackPlatinum and his siblings were formed when Makraites (CoachSDot) ship crash landed on the PvZ planet. After creation, they participated in the events that formulated the FTS universe as we know it. Then they were forgotten to history. They then went off to form their own realm.
In FTS 5 the old JackPlatinum was reintroduced after a war with the illuminati leader destroyed the realm of forgotten characters. He then met present time JackPlatinum in the woods and instantly hated him. He has the same powers as regular JackPlatinum except is more dense and cannot turn into slag, instead always being solid.
There was a time when all was well with FTS. Then I, JackPlatinum, Ruined it with 2 posts. I set myself straight later, but they were still bad. In the posts, PSI Seven summoned me to the Falling World to help, And then I got in a battle with the Illuminati. Later, that past version of me was reintroduced as Old JackPlatinum.
JackPlatinum eventually ended up in a big city, where he became a musician. Later, when "that idiot IRL Jack" starts FTS 7, JackPlatinum comes to help. His brothers and sisters all work for Seven.