No observed cheques. Organisations of this type rarely announce deals, so this says nothing about their activity.
From their own site: “Tethys is a Single Family Office with the mission to efficiently and profitably deploy capital in ideas and people that can play an impactful role on economic progress, globally and in Greece.”
An announcement gives the size of the round, not the size of this investor's cheque. The only rounds that imply a cheque are those where they were the sole named investor.
Something wrong here? Tell us — corrections are free and need no account.