Merin Aspic is the Consul's grandfather, and the Consul's tale is more about him than about the Consul. When the tale beings, Merin is mad about something: "The day is perfect and I hate it for being so" (6.130). Wow, what did that day to do him? Kill his mom? (Well, it killed his wife. Oops.)
It's less the day and more the entire universe—or at least the Hegemony, which might as well be the entire universe. Merin's story shows us the less-than-peaceful ways that the Hegemony inducts planets into the WorldWeb , and that these planets don't necessarily want to be a part of it. Maui-Covenant will lose many of its natural resources, even its animals, if the Hegemony takes over.
Merin, an officer in the Hegemony's self-defense force (irony alert! The SDF seems to start more conflicts than it defends against) is in love with Siri. No, Siri isn't his iPhone's little helper, but a beautiful girl on the planet Maui-Covenant, due to be inducted into the Web.
Merin and Siri make love, swim with dolphins, and have children and grandchildren, all before Merin is in his mid-20s. This is possible because Merin lives primarily on a starship, traveling faster than the speed of light. Time passes much more slowly for him than it does for Siri. His experience with her is the opposite of Sol and Rachel's: instead of aging backwards, he watches Siri rapidly approach old age, living his life like the fast-forward button on his DVR is stuck. He only sees her seven times before she dies.
There is a lot of tension between the SDF (special defense force) and the residents of Maui-Covenant, especially Siri, who wants to resist assimilation into the Hegemony at all costs. Merin even sees his friend, Mike Osho, die in a street fight between Maui-Covenant rebels and SDF forces.
All of this tension serves to motivate Merin, and the Consul by extension, to rebelling against the Hegemony. He uses the bomb Siri leaves him after her death to blow up the Hegemony's farcaster portal before it is activated. He knows it is futile, but doesn't stop him from trying to delay the inevitable: "Later, when the battles are won and the world is theirs, I will tell them about her. I will sing to them of Siri" (6.459). It's hard to say he was wrong.
Merin's story is almost completely different than all the others. Religion plays hardly any part in it. The Shrike doesn't even appear. His story seems to show an idyllic time and place where neither of these destructive exist. Merin's story shows the death of carefree innocence at the hands of human greed. It shows why the Consul decided to become an Ouster spy, opening up the Time Tombs. He's trying to destroy the Hegemony and eliminate the mistakes of humanity.
And if a few million—or billion—people die in the process, oh well.