Part 20: Beach Blanket Blasto
Beach Blanket BlastoMe 'n Lazyfire put on our board shorts and flip-flops and head on over to Virmire to check in on the STG. Turns out Saren has built a secret lair and is breeding an army of Krogan. The actual science behind this is never explained, nor is the fact that since Krogan are a very long-lived species how they're accelerating them to adulthood in what's assumedly a couple of weeks. Don't blame the game for this, cloning is a common sci-fi trope and nobody ever explains how all their clones are automatically grownups.
Because we're good people and bothered to do Wrex's personal quest, he's upset but sides with us in the matter. Should you skip it, he gets really mad and then Ashley kills him rather spontaneously. Like no signal from you, just blows him away while you're arguing with him. I don't know why you'd want to kill Wrex as he's completely awesome, but should you choose to do it then the ME universe becomes a much worse place, IMO. His fill-in for the rest of the series is his half-brother Wreav, who is way more regressive in his thinking and will probably end up with the full extinction of his species.
Kirrahe is an awesome dude (bit of a cloaca, though) and the first time I heard his speech it was pretty moving. If you do everything right in the next section then he survives and turns up again in 3, where he is also awesome.