From The Heretic Knowledge Vault
He and his twin sister Liz are first seen in Saus, conducting surveillance on PC Argus as he and Brother Miguel try to figure out what became of the enigmatic Father Egbert. At first this doesn't seem like a big deal; the Arganials, not named at this point, simply have Argus casually staked out as he wanders around downtown Saus, and again as he joins Miguel at the Reformed temple on the outskirts of town. When their uncle "Arkie" shows up, masquerading as Gordon Grumiel (the last person known to have seen Egbert before he disappeared after gating into Saus), he calls them "Leo" and "Leilani" and tries unsuccessfully to get Miguel and Argus to take them along on their quest. After this encounter, they aren't seen again for a while.
He next shows up in the countryside outside the small town of Heamish, as he, Liz and Arkie cross a pass at the west end of the rock formation known as the Sleeping Sexton. As it happens, Argus has holed up in a magical foxhole on this pass as Miguel and Sister Rose go to seek help from some military friends north of the Sleeping Sexton, and Liz, who appears to be a low-level magic user, recognizes his hidey-hole, although she doesn't do anything about it. The badinage accompanying this encounter hints that Buddy doesn't share his sister's magical inclinations, but rather prefers a more straightforward, pull-out-a-gun-and-blow-'em-away approach to problem solving. This is the first time that Liz's and Buddy's actual names are used, and it's the last time we see them alive, apart from a distant view by Egbert somewhere to the south that's mentioned as a vignette.
He makes the sad transition from "Living" to "Living Impaired," as do his relatives, as a result of an unfortunate encounter in the weird ghost town of Centoriel. This happens offstage, but we know that it leads to the male Arganials being messily incinerated at the site, while something even more ghastly happens to Liz, if that's possible. Buddy's death is particularly painful, as apparently he's just barely in the lethal radius of a fireball or some such, absorbing enough damage to be fatal, but slowly and painfully as opposed to the instant cooking that befalls his uncle. Even so, this is probably preferable to what happens to his sister once she's teleported to the Malletarian compound, so he's avenged for the abuse that sis heaped on him at the Sleeping Sexton -- sort of.