Fear the Walking Dead unveiled its real villains of season 5, but in doing so, the show suddenly killed off Logan, whose reason for wanting to take the oil fields connected to the new group that was introduced in the latest episode. A significant part of Fear the Walking Dead season 4 and season 5 has been helping others, specifically adhering to the line, "Take what you need, leave what you don't." As it turns out, Logan came up with that line himself a while back.
Logan and his partner, Polar Bear, used to drive trucks around their area and place packages near mile markers, encouraging people to take only the supplies they truly needed to keep going. One day, Sarah and Wendell took Polar Bear's rig, and so, he wasn't able to help a woman who had been trapped at one of their rest stops. Logan ran to help that woman himself but was too late, which is how he ended up meeting and joining up with a group of horse riders who are trying to rebuild the world.
Although they weren't named, Fear the Walking Dead's new group - introduced in "Leave What You Don't" - is led by a woman named Virginia (Colby Minifie) who travels on horseback and is dressed in old Western clothes. Her group is expanding and they plan on rebuilding the world, though people may not always agree with their methods. After meeting Logan, they contracted him to obtain gasoline for them to use to expand their efforts. That's why Logan and his team has been chasing the convoy all of this time.
It became clear in "Leave What You Don't" that Logan and his team were in over their heads with this group, and they were starting to worry - perhaps that had exceeded their deadline already. They quickly became careless with the fire at the oil field, and it drew several dozens of walkers from the surrounding area. Ultimately, Logan saw reason in what the convoy has been doing with helping people, and he chose to not fight them. But it's that decision that got him and his team killed, as Virginia's people shot and killed them.
Virginia's group doesn't appear to have any connections to the helicopter group that took Rick Grimes, seeing as they are still trying to build and they need gasoline to do so. The helicopter group already had enough fuel to travel by air; they didn't need horses. But it's unlikely that they are the Commonwealth either, as that group is presumably being saved for The Walking Dead. It wouldn't be smart to relegate them to the spinoff series. With only a few episodes of Fear the Walking Dead season 5 left, hopefully, more details arise regarding Virginia's new group.