Returning to Romania in the early 1920s he entered the Romanian diplomatic service and was appointed consul at Sarandë in order to influence the local Aromanian population.

[1] Shortly after the presumed amnesty, he arrived in Athens[2] as the "vice president of the National Petroleum Company of Romania", as an oil importer.

He rented a flat in the fashionable Kolonaki district, and frequented the bars and cafes of Piraeus, where he was involved in a brawl with a Greek navy captain.

Diamandi frequently traveled to Rhodes (which was at the time an Italian possession), managing to attract the attention of the Greek Counter-intelligence Services.

On 1 March 1942 Diamandi issued an ample Manifesto which was published in the local press and republished by Stavros Anthemides in 1997 (in his book on the Vlachs of Greece; see bibliography).

Towards the second year of the Italian occupation, guerilla actions broke out in the area, between the Greek Resistance supported by the Allied Forces and the Italo-German side.

[3] Matoussi escaped, first to Athens then to Romania too, while Rapoutikas was shot dead by one of the Greek factions involved in guerilla activities just outside Larissa (the Greeks then tied his corpse on the back a donkey and paraded him through the Aromanian villages of the Pindus – this was intended in order to scare the local populace and as a final proof that the Roman Legion had reached its end).

According to the German scholar Thede Kahl, Diamandi was for a while Kingdom of Romania's Consul in the Albanian port Vlorë just opposite across the strait of the Italian town of Otranto.

{{cite web}}: CS1 maint: bot: original URL status unknown (link) or Mark Mazower) make sure that they clearly distance themselves from Diamandi hence bestowing upon him apelatives like "extremist" and "shameful".