"Another tale of Yoda's past involves stopping a swath of destruction cut by Dark Jedi from Bpfassh. One of these dark siders had gotten as far as Dagobah, were Yoda bested him in direct confrontation. The Bpfasshi Jedi died, his dark Force absorbing into and twisting a nearby tree -- forming a dark side nexus. It is believed that Yoda chose Dagobah as his hiding place due to the dark side energies emanating from the tree. From a distance, Force-users like the Emperor would not detect Yoda since the master's bright light side presence would be canceled by the Bpfasshi dark side presence."
"Another tale of Yoda's past involves stopping a swath of destruction cut by Dark Jedi from Bpfassh. One of these dark siders had gotten as far as Dagobah, were Yoda bested him in direct confrontation. The Bpfasshi Jedi died, his dark Force absorbing into and twisting a nearby tree -- forming a dark side nexus. It is believed that Yoda chose Dagobah as his hiding place due to the dark side energies emanating from the tree. From a distance, Force-users like the Emperor would not detect Yoda since the master's bright light side presence would be canceled by the Bpfasshi dark side presence."