Defend Austria is a citizens’ initiative that describes itself as “conservative” and was founded in Upper Austria, Vienna and Lower Austria in 2024. They support the FPÖ with mobilisations for pro-FPÖ demonstrations and run an online shop. Its members are relatively young and often dress in black.
Sources:

• https://www.heute.at/s/rechtsextreme-planen-in-wien-demo-am-wahlsonntag-120061246
• t.me/defendaustria