In the complex mosaic of the new Syria, the old battle against the group calling itself Islamic State (IS) continues in the Kurdish-controlled north-east. It's a conflict that has slipped from the headlines - with bigger wars elsewhere.
But Kurdish counter-terrorism officials have told the BBC that IS cells in Syria are regrouping and increasing their attacks.
Walid Abdul-Basit Sheikh Mousa was obsessed with motorbikes and finally managed to buy one in January.
The 21-year-old only had a few weeks to enjoy it. He was killed in February fighting against IS in north-eastern Syria.
Walid was so keen to take on the extremists that he ran away from home, aged 15, to join the Kurdish-led Syrian Democratic Forces (SDF). They brought him back because he was a minor, but accepted him three years later.
