Assuming the Tnutipun Evil Plot ["The Tnuctipun Plot"] and that Outsiders were not a power in the ]
Galaxy at the time of the [Tnuctipun-]Slaver War (they seem to likely be of extragalactic origin):
Problem: Outsiders recognize Tnuctipun as possible threat.
Solution: Eliminate threat
Problem: Outsiders don't want to do the dirty work.
Solution: Get the races of Known Space to do it. The Puppeteers are the only sufficiently developed race
in / about Known Space. Give them the technology to make the species of Known Space sufficiently spacefaring that
they'll be ready for the war. Likely similar other programs elsewhere. Wait for races to discover / trade with the
Puppeteers. Build the Ringworld to become a headquarters in the war. Seed it with races isolated on the maps with
plans to move them to more breeding room when the time comes.
Problem: Discovery of the Pak
Solution: Wipe out fleeing Pak from Pakhome. Use the information gained to supercharge your army.
Problem: Protectors are really, really mean.
Solution: Soften them. The Earthers seem less aggressive. This is likely due to a more advanced breeder
stage, cultural differences, and a long greater independence on protectors. Genetic manipulation is best done passively.
Seed the Ring with hominids. Work them to be more dependent on each other, so their protectors might be able to cooperate.
Presumably we caught the breeding plan before it complete. Why?
Problem: Ring is being interfered with by hominid civilization that developed.
Implications: Assumption that low raw-material would prevent appreciable civilizations was wrong.
Solution: Have Puppeteers eliminate the civilization.
Problem: Ring is off balance due to lack of attitude jets.
Solution: Have Puppeteers send an expedition that might repair it.
The Outsiders have always appeared to have little interest in other races because they are just so darn powerful.
Perhaps they realize that it is easier to get someone else to do it. The best motivation is self interest. Put the
humans in a situation where they, who accidentally have proven to be a very good warrior, in a situation where they
don't have a choice.
The Outsiders tipped their hand in Ringworld Throne. Why was their ship there?
The core explosion will eventually force humans off of Earth. When we let them "discover" the ring, it'll be
the perfect place for all of the Races of Known Space to prepare for the coming war. What comes with them? The basic
infrastructure of a Ringworld space fleet and the Teela Genes. When it comes that the humans are indistinguishible from
the natives and the ways of space lanes are established with the Ring at its center, the war begins. What do the Outsiders
care? It's hotlife. The only thing special about the Tnuctipun is that they made the starseeds. Start messing with things
on a galactic scale, you're in Outsider territory. Why else would the Outsiders eventually make the Ring population so
diverse? Fragmentation. A galactic civilization composed of all the races of Known Space will be too fragmented to ever be
a unified threat. To make sure they're all being made docile. The Humans Teela Genes, the friendly protectors of the ring,
the newly docile Kzin— all made docile (but not impotent) by the first race we made so docile yet quietly dangerous,
our first henchmen, the Puppeteers.
