Email Guardian is a cloud email security service from Iberlayer. It filters spam and malicious messages, analyses attachments and links, detects fraud and monitors suspicious domains. According to the vendor, it also supports DMARC. There is no software or hardware to install: you point your domain's MX records at the service, in coordination with Iberlayer. Encrypted copies of messages (AES256) are kept for up to five days so that email can be restored if the customer's own infrastructure fails.
Iberlayer S.L. is a Spanish company with an office in Tres Cantos near Madrid and has offered email filtering since 2012. The sources consulted name no parent company outside Spain. The vendor describes its service as a 100% European cloud but does not name a data-centre location on its website. Because all of your email passes through the service, it is worth asking for the exact location and the sub-processors beforehand. As a Spanish provider, Iberlayer falls under European law.