Untrusting is an understatement. Vader is paranoid and that may be underselling it. But that probably is to be expected when the man who often professed to love you was also seriously abusing you and designing you worst traumas and nightmares, then demanded a vow of fealty and only after told you the price would be to slaughter small children who came running to you for salvation.

Which he wouldn't admit to still having nightmares of.

Often. More so now that has brain could too easily put his small daughter's face among the children.

"This is a war zone. Of course you'll need a favor." There's a scoff to his voice. "Which could range from clean drinking water to rescue from interrogation to needing someone silenced."