Most likely yes you will need to know those programs as they will be the ones they use and you will be required to use. You may be able to persuade them to let you use blender, or even learn maya on the job. You never know what their answer will be until you ask.

Note the job title: Lead character designer

I'm guessing they've got other requirements in there like 6+ years of industry experience and 3+ major games, and probably something in their about prior team leadership experience preferred.

They're looking for a person to lead a team. To lead a team you need experience in far more than just the programs. You need experience with the entire flow of game development.

While your specific skills in Blender may be great, the team is looking for someone with experience in Maya and Zbrush so they can immediately start working -- being productive -- on the very first day. If you were applying for a lower position, perhaps a regular non-lead character designer or an entry level character designer, your skills at character design could potentially be directly applicable and worth it to the company to help you through the learning curve.

Apply for the job if you want but it will likely be rejected.

Much better to assume that if they are looking for a new team lead, they are probably also looking for additional team members below the leadership role. Apply for that job instead. If you don't see the job listed on their site, contact their HR person with your resume anyway.

Given that the studio you apply for might already have used the two tools for years, have trained 3D artists with lots of expierience in both tools (but maybe zero expierience in Blender), and you are expected to become not only a teamworker (thus being able to work together with other artists.... how do you do that if you use different tools?), but also to be a lead to artists using both these tools... you will be expected to understand these tools.

Also, be aware that while most tools nowadays are able to produce pretty much similar results given an expierienced user is doing the work, Blender sticks out as it has one important feature missing: it doesn't allow you to create and edit Vertex Normals. These get automatically generated on export AFAIK, but some things remain: Smooth shading WILL look different to what you can achieve with other tools, and to achieve a hard seam Blender needs to duplicate vertices instead of just duplicating the vertex normals.

Most of the time exporting and importing between Blender and other tools works just fine, but some things will not work, if Blender is anywhere in the pipeline: try to create a model in a tool that uses Vertex normals for smooth shading, import it to blender, export it again and open it in the original application. Most probably your smooth shading is screwed up, and you would have to go and edit all the vertex normals back to the original values.

Long story short: Blender is a fine 3D Application as long as you either use it standalone, or have a clear pipeline that will preferrably start with Blender. If you export/import between Blender and other applications, things will at some point break.

So using Blender in a Team that uses mostly ZBrush and Maya is a BAD idea. I hope the studio heads also know this and will tell you to either adapt to their pipeline or get lost.