So, I read this story (novel/book) a while ago, but now cannot remember the name. Here is the synopsis, as I remember it (please note that my memory could be faulty): The story begins in London, where two brothers are having an argument, over a girl. Somehow one enters through a portal that opens up in the London Underground. The other eventually follows him, but because the Portals transport through Space/Time, his brother is now a successful interstellar trader (The following brother does not yet know this). The main conflict at this point is the sentient red cloud (that I can't remember the name of) that is encroaching on the area where these people are hanging out, which is called The Gnarl. Eventually it is figured out that the Gnarl is really an ancient weapon called "The Torch" that only the other brother can operate. The cloud is beaten back, and... That's as much as I can remember. If anyone has any idea what I'm babbling about, please give me your wisdom; if I can help clarify anything that will lead to the identification, please let me know. ALso, I feel like I may have read about this story description on this site, but I am not sure. Again, THANK YOU!
The novel is The Recollection by Gareth L. Powell. Partial synopsis lifted from Amazon:
When his brother disappears into a bizarre gateway on a London Underground escalator, failed artist Ed Rico and his brother's wife Alice have to put aside their feelings for each other to go and find him. Their quest through the 'arches' will send them hurtling through time, to new and terrifying alien worlds.