Depends on your budget. For that hairline, you would need a lacefront wig ($$$!) or a wig that has wefts going backwards, such as Arda's Malinda or Glinda. If either of them is available in Dark Ash Blonde, they might work for Oak. Another option is to create a fake hairline on a spikable wig, using this tutorial
. Again, Arda or Epic Cosplay are your best options as they both have wefts available for purchase. Good luck and hope this helps!