Dissolve the Bonds of Kinship question.

Close, but not quite. You have the replacement part correct - the first half of the power will result in 1 City and 5 Explorers.

The damage part is slightly different than you describe. Explorers damage buildings (Towns and Cities) and buildings damage Explorers, but Explorers do not damage other Explorers (nor do buildings damage other buildings).

So in your example, the 5 Explorers deal 5 damage to the City, destroying it (the extra 2 damage is lost) and the City deals 3 damage to the Explorers (destroying 3 Explorers). The result is 2 Explorers, which are then pushed out of the target land.

thank u!

process is same to Instruments of Their Own Ruin?

in FAQ (process is same to Instruments of Their Own Ruin), 1 city, 1 town, 1 explorer is all destroy.

No. Remember that Strife is attached to a specific invader, not a land (the way the other spirit tokens work). So, if you have a land with a city, a town, and an explorer (and no Strife) and use Instruments of Their Own Ruin there, the following would happen.

1. Add 1 Strife; let's say to the city, though you could add it to one of the others to achieve a different effect.
2. Each Invader with Strife (just the city) deals damage to the other Invaders in the land. So the city will deal 3 damage to the town and the explorer, destroying them.

This leaves the land with a city with 1 Strife attached to it.

Does that clarify things?