Haruspicy

Haruspicy is the art of shuffling around your family tree to fit different relatives in to it. These potential relatives will provide one of two types of benefit: either a small passive benefit, such as being able to look after more Poisons, or a one-time benefit, calling in a favour from that relative (and losing your relation to them in the process). Some example Relatives are shown below:

Generally, the more potent the effect of a relative, the harder it will be to fit them into your family tree - after all, everyone only has so much to give, so the fewer people they're related to, the more potent those relationships become. Conversely, Haruspicy allows for some Relatives to be almost inferred: places on the family tree which provide no benefit except to connect other parts, as shown below.