How were Wilhelm II and Nicholas II of Russia related?

Nicholas II of Russia was the second cousin once removed of Wilhelm II.

Their nearest shared ancestors were Frederick William III of Prussia and Louise of Mecklenburg-Strelitz.

That is only the shortest of 6 separate lines of descent between them.

The line between them

1. Wilhelm II 1859–1941
2. Frederick III, German Emperor 1831–1888
3. Wilhelm I 1797–1888
4. Frederick William III of Prussia 1770–1840
5. Alexandra Feodorovna 1798–1860
6. Alexander II of Russia 1818–1881
7. Alexander III of Russia 1845–1894
8. Nicholas II of Russia 1868–1918

See the line on the tree